Sandcastles (The documentation builders) now support Visual Studio 2010 integration. In this light I have added a Documentation project to the DocX solution. This will help to keep the DocX.chm file up to date.

DocX.sln

 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Examples", "Examples\Examples.csproj", "{F3022BB7-0E40-4C80-A495-37FEAF3671AB}"
 EndProject
+Project("{7CF6DF6D-3B04-46F8-A40B-537D21BCA0B4}") = "Documentation", "Documentation\Documentation.shfbproj", "{1EB1EE8F-9978-425B-A742-533DCCEB4811}"
+EndProject
 Global
 	GlobalSection(TeamFoundationVersionControl) = preSolution
 		SccNumberOfProjects = 5
 		SccProjectUniqueName3 = Examples\\Examples.csproj
 		SccProjectName3 = Examples
 		SccLocalPath3 = Examples
-		SccProjectUniqueName4 = ConsoleApplication4\\ConsoleApplication4.csproj
-		SccProjectName4 = ConsoleApplication4
-		SccLocalPath4 = ConsoleApplication4
+		SccProjectUniqueName4 = Documentation\\Documentation.shfbproj
+		SccProjectName4 = Documentation
+		SccLocalPath4 = Documentation
 	EndGlobalSection
 	GlobalSection(TestCaseManagementSettings) = postSolution
 		CategoryFile = DocX.vsmdi
 		{F3022BB7-0E40-4C80-A495-37FEAF3671AB}.Release|Mixed Platforms.Build.0 = Release|x86
 		{F3022BB7-0E40-4C80-A495-37FEAF3671AB}.Release|x86.ActiveCfg = Release|x86
 		{F3022BB7-0E40-4C80-A495-37FEAF3671AB}.Release|x86.Build.0 = Release|x86
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Release|Mixed Platforms.Build.0 = Release|Any CPU
+		{1EB1EE8F-9978-425B-A742-533DCCEB4811}.Release|x86.ActiveCfg = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

DocX/DocX.cs

             UpdateCustomPropertyValue(this, cp.Name, cp.Value.ToString());
         }
 
-
-
         internal static void UpdateCustomPropertyValue(DocX document, string customPropertyName, string customPropertyValue)
         {
-            foreach (XElement e in document.mainDoc.Descendants(XName.Get("fldSimple", w.NamespaceName)))
-            {
-                string attr_value = e.Attribute(XName.Get("instr", w.NamespaceName)).Value.Replace(" ", string.Empty).Trim();
-                string match_value = string.Format(@"DOCPROPERTY  {0}  \* MERGEFORMAT", customPropertyName).Replace(" ", string.Empty);
+            // A list of documents, which will contain, The Main Document and if they exist: header1, header2, header3, footer1, footer2, footer3.
+            List<XElement> documents = new List<XElement>{ document.mainDoc.Root };
 
-                if (attr_value.Equals(match_value, StringComparison.CurrentCultureIgnoreCase))
-                {
-                    XElement firstRun = e.Element(w + "r");
-                    XElement firstText = firstRun.Element(w + "t");
-                    XElement rPr = firstText.Element(w + "rPr");
+            // Check if each header exists and add if if so.
+            #region Headers
+            Headers headers = document.Headers;
+            if (headers.first != null)
+                documents.Add(headers.first.Xml);
+            if (headers.odd != null)
+                documents.Add(headers.odd.Xml);
+            if (headers.even != null)
+                documents.Add(headers.even.Xml); 
+            #endregion
 
-                    // Delete everything and insert updated text value
-                    e.RemoveNodes();
+            // Check if each footer exists and add if if so.
+            #region Footers
+            Footers footers = document.Footers;
+            if (footers.first != null)
+                documents.Add(footers.first.Xml);
+            if (footers.odd != null)
+                documents.Add(footers.odd.Xml);
+            if (footers.even != null)
+                documents.Add(footers.even.Xml);
+            #endregion
 
-                    XElement t = new XElement(w + "t", rPr, customPropertyValue);
-                    Novacode.Text.PreserveSpace(t);
-                    e.Add(new XElement(firstRun.Name, firstRun.Attributes(), firstRun.Element(XName.Get("rPr", w.NamespaceName)), t));
-                }
-            }
+            // Process each document in the list.
+            foreach (XElement doc in documents)
+            {
+                foreach (XElement e in doc.Descendants(XName.Get("instrText", w.NamespaceName)))
+                {
+                    string attr_value = e.Value.Replace(" ", string.Empty).Trim();
+                    string match_value = string.Format(@"DOCPROPERTY  {0}  \* MERGEFORMAT", customPropertyName).Replace(" ", string.Empty);
 
-            //#region Headers
-            //foreach(PackagePart pp in document.headers)
-            //{
-            //    XDocument header = XDocument.Load(new StreamReader(pp.GetStream()));
-
-            //    foreach (XElement e in header.Descendants(XName.Get("fldSimple", w.NamespaceName)))
-            //    {
-            //        if (e.Attribute(XName.Get("instr", w.NamespaceName)).Value.Trim().Equals(string.Format(@"DOCPROPERTY  {0}  \* MERGEFORMAT", customPropertyName), StringComparison.CurrentCultureIgnoreCase))
-            //        {
-            //            XElement firstRun = e.Element(w + "r");
-
-            //            // Delete everything and insert updated text value
-            //            e.RemoveNodes();
-
-            //            XElement t = new XElement(w + "t", customPropertyValue);
-            //            Novacode.Text.PreserveSpace(t);
-            //            e.Add(new XElement(firstRun.Name, firstRun.Attributes(), firstRun.Element(XName.Get("rPr", w.NamespaceName)), t));
-            //        }
-            //    }
-
-            //    using (TextWriter tw = new StreamWriter(pp.GetStream()))
-            //        header.Save(tw);
-            //} 
-            //#endregion
-
-            //#region Footers
-            //foreach (PackagePart pp in document.footers)
-            //{
-            //    XDocument footer = XDocument.Load(new StreamReader(pp.GetStream()));
+                    if (attr_value.Equals(match_value, StringComparison.CurrentCultureIgnoreCase))
+                    {
+                        XNode node = e.Parent.NextNode;
+                        bool found = false;
+                        while (true)
+                        {
+                            if (node.NodeType == XmlNodeType.Element)
+                            {
+                                var ele = node as XElement;
+                                var match = ele.Descendants(XName.Get("t", w.NamespaceName));
+                                if (match.Count() > 0)
+                                {
+                                    if (!found)
+                                    {
+                                        match.First().Value = customPropertyValue;
+                                        found = true;
+                                    }
+                                    else
+                                    {
+                                        ele.RemoveNodes();
+                                    }
+                                }
+                                else
+                                {
+                                    match = ele.Descendants(XName.Get("fldChar", w.NamespaceName));
+                                    if (match.Count() > 0)
+                                    {
+                                        var endMatch = match.First().Attribute(XName.Get("fldCharType", w.NamespaceName));
+                                        if (endMatch != null && endMatch.Value == "end")
+                                        {
+                                            break;
+                                        }
+                                    }
+                                }
+                            }
+                            node = node.NextNode;
+                        }
+                    }
+                }
 
-            //    foreach (XElement e in footer.Descendants(XName.Get("fldSimple", w.NamespaceName)))
-            //    {
-            //        if (e.Attribute(XName.Get("instr", w.NamespaceName)).Value.Trim().Equals(string.Format(@"DOCPROPERTY  {0}  \* MERGEFORMAT", customPropertyName), StringComparison.CurrentCultureIgnoreCase))
-            //        {
-            //            XElement firstRun = e.Element(w + "r");
+                foreach (XElement e in doc.Descendants(XName.Get("fldSimple", w.NamespaceName)))
+                {
+                    string attr_value = e.Attribute(XName.Get("instr", w.NamespaceName)).Value.Replace(" ", string.Empty).Trim();
+                    string match_value = string.Format(@"DOCPROPERTY  {0}  \* MERGEFORMAT", customPropertyName).Replace(" ", string.Empty);
 
-            //            // Delete everything and insert updated text value
-            //            e.RemoveNodes();
+                    if (attr_value.Equals(match_value, StringComparison.CurrentCultureIgnoreCase))
+                    {
+                        XElement firstRun = e.Element(w + "r");
+                        XElement firstText = firstRun.Element(w + "t");
+                        XElement rPr = firstText.Element(w + "rPr");
 
-            //            XElement t = new XElement(w + "t", customPropertyValue);
-            //            Novacode.Text.PreserveSpace(t);
-            //            e.Add(new XElement(firstRun.Name, firstRun.Attributes(), firstRun.Element(XName.Get("rPr", w.NamespaceName)), t));
-            //        }
-            //    }
+                        // Delete everything and insert updated text value
+                        e.RemoveNodes();
 
-            //    using (TextWriter tw = new StreamWriter(pp.GetStream()))
-            //        footer.Save(tw);
-            //}
-            //#endregion
+                        XElement t = new XElement(w + "t", rPr, customPropertyValue);
+                        Novacode.Text.PreserveSpace(t);
+                        e.Add(new XElement(firstRun.Name, firstRun.Attributes(), firstRun.Element(XName.Get("rPr", w.NamespaceName)), t));
+                    }
+                }
+            }
         }
 
         public override Paragraph InsertParagraph()

DocX/DocX.csproj

     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <DocumentationFile>
-    </DocumentationFile>
+    <DocumentationFile>bin\Debug\DocX.XML</DocumentationFile>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     </Compile>
   </ItemGroup>
   <ItemGroup>
-    <None Include="Help\Changes in this version 1.0.0.10.docx" />
-    <None Include="Help\DocX v1.0.0.10 - Documentation.chm" />
-    <None Include="Help\Read Me.docx" />
     <None Include="StrongNameFile.pfx" />
   </ItemGroup>
   <ItemGroup>

Documentation/Documentation.shfbproj

+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
+  <PropertyGroup>
+    <!-- The configuration and platform will be used to determine which
+         assemblies to include from solution and project documentation
+         sources -->
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <SchemaVersion>2.0</SchemaVersion>
+    <ProjectGuid>{1eb1ee8f-9978-425b-a742-533dcceb4811}</ProjectGuid>
+    <SHFBSchemaVersion>1.9.3.0</SHFBSchemaVersion>
+    <!-- AssemblyName, Name, and RootNamespace are not used by SHFB but Visual
+         Studio adds them anyway -->
+    <AssemblyName>Documentation</AssemblyName>
+    <RootNamespace>Documentation</RootNamespace>
+    <Name>Documentation</Name>
+    <!-- SHFB properties -->
+    <OutputPath>Help\</OutputPath>
+    <HtmlHelpName>Documentation</HtmlHelpName>
+    <Language>en-US</Language>
+    <HelpFileFormat>HtmlHelp1</HelpFileFormat>
+    <IndentHtml>False</IndentHtml>
+    <FrameworkVersion>.NET 4.0.30319</FrameworkVersion>
+    <KeepLogFile>True</KeepLogFile>
+    <DisableCodeBlockComponent>False</DisableCodeBlockComponent>
+    <CppCommentsFixup>False</CppCommentsFixup>
+    <CleanIntermediates>True</CleanIntermediates>
+    <SyntaxFilters>Standard</SyntaxFilters>
+    <SdkLinkTarget>Blank</SdkLinkTarget>
+    <RootNamespaceContainer>False</RootNamespaceContainer>
+    <PresentationStyle>vs2005</PresentationStyle>
+    <Preliminary>False</Preliminary>
+    <NamingMethod>Guid</NamingMethod>
+    <HelpTitle>DocX - A Sandcastle Documented Class Library</HelpTitle>
+    <FeedbackEMailLinkText>coffey.cathal%40gmail.com</FeedbackEMailLinkText>
+    <FeedbackEMailAddress>coffey.cathal%40gmail.com</FeedbackEMailAddress>
+    <ContentPlacement>AboveNamespaces</ContentPlacement>
+    <DocumentationSources>
+      <DocumentationSource sourceFile="..\DocX\DocX.csproj" />
+    </DocumentationSources>
+    <SccProjectName>SAK</SccProjectName>
+    <SccProvider>SAK</SccProvider>
+    <SccAuxPath>SAK</SccAuxPath>
+    <SccLocalPath>SAK</SccLocalPath>
+    <WorkingPath>%temp%\</WorkingPath>
+  </PropertyGroup>
+  <!-- There are no properties for these groups.  AnyCPU needs to appear in
+       order for Visual Studio to perform the build.  The others are optional
+       common platform types that may appear. -->
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x86' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x64' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x64' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|Win32' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|Win32' ">
+  </PropertyGroup>
+  <ItemGroup>
+    <Folder Include="Help\" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="Help\Documentation.chm" />
+  </ItemGroup>
+  <!-- Import the SHFB build targets -->
+  <Import Project="$(SHFBROOT)\SandcastleHelpFileBuilder.targets" />
+</Project>

Documentation/Documentation.shfbproj.vspscc

+""
+{
+"FILE_VERSION" = "9237"
+"ENLISTMENT_CHOICE" = "NEVER"
+"PROJECT_FILE_RELATIVE_PATH" = ""
+"NUMBER_OF_EXCLUDED_FILES" = "0"
+"ORIGINAL_PROJECT_FILE_PATH" = ""
+"NUMBER_OF_NESTED_PROJECTS" = "0"
+"SOURCE_CONTROL_SETTINGS_PROVIDER" = "PROVIDER"
+}