Just a little cool nant task I would like to share.
It is mainly targeted developers wich are building packages via build script.

The nant task xmlpeek and xmlpoke are quite simple and it is difficult to append xml nodes to xml files. You can do it though but the build script will be harder to maintain.

The task can take a node list from a source xml document and append it to a node in a target xml document

<appendxml
      sourcefile="${dir}/Publication.Module.Dictionary.xml" 
      sourcexpath="/umbPackage/DictionaryItems/DictionaryItem" 
      targetfile="${dir}/package.xml" 
      targetxpath="/umbPackage/DictionaryItems"  />

The source code for the task is in the bottom

Example files:

AppendDictionaries.build

<?xml version="1.0"?>
<project name="Foundation" 
default="">
  <property name="dir" 
value="${directory::get-current-directory()}" />
  <target 
      name="AppendDictionaries" description="Add the publication and news 
            module dictionaries into the main package file">
    <appendxml
      sourcefile="${dir}/Publication.Module.Dictionary.xml" 
      sourcexpath="/umbPackage/DictionaryItems/DictionaryItem" 
      targetfile="${dir}/package.xml" 
      targetxpath="/umbPackage/DictionaryItems"  />
    <appendxml 
      sourcefile="${dir}/News.Module.Dictionary.xml" 
      sourcexpath="/umbPackage/DictionaryItems/DictionaryItem" 
      targetfile="${dir}/package.xml" 
      targetxpath="/umbPackage/DictionaryItems"  />
  </target>
</project>

package.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<umbPackage>
    <files />
    <info>
        <package>
            <name>The cool foundation</name>
            <version></version>
            <license url="http://www.opensource.org/licenses/mit-license.php">MIT license</license>
            <url>http://www.cpalm.dk</url>;
            <requirements>
                <major>4</major>
                <minor>0</minor>
                <patch>3</patch>
            </requirements>
        </package>
        <author>
            <name>Christian Palm</name>
            <website>http://www.cpalm.dk</website>;
        </author>
        <readme><![CDATA[]]></readme>
    </info>
    <Documents></Documents>
    <DocumentTypes>    </DocumentTypes>
    <Templates></Templates>
    <Stylesheets></Stylesheets>
    <Macros />
    <DictionaryItems />
    <Languages />
    <Actions></Actions>
    <DataTypes></DataTypes>
    <control></control>
</umbPackage>

Publication.Module.Dictionary.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<umbPackage>
 <DictionaryItems>
    <DictionaryItem Key="PublicationModule">
      <Value LanguageId="1" LanguageCultureAlias="en-US">
        <![CDATA[Testing]]>
      </Value>
    <DictionaryItem Key="PublicationModule-Title">
      <Value LanguageId="1" LanguageCultureAlias="en-US">
        <![CDATA[Publication module]]>
      </Value>
      </DictionaryItem>
    </DictionaryItem>
  </DictionaryItems>
</umbPackage>

News.Module.Dictionary.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<umbPackage>
 <DictionaryItems>
    <DictionaryItem Key="NewsModule">
      <Value LanguageId="1" LanguageCultureAlias="en-US">
        <![CDATA[Testing]]>
      </Value>
      <DictionaryItem Key="NewsModule-Title">
        <Value LanguageId="1" LanguageCultureAlias="en-US">
          <![CDATA[News module]]>
        </Value>
      </DictionaryItem>
     </DictionaryItem>
  </DictionaryItems>
</umbPackage>

Updated package.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<umbPackage>
 <files />
    <info>
        ...
        <!-- skipped in example -->
        ...
    </info>
    <Documents></Documents>
    <DocumentTypes></DocumentTypes>
    <Templates></Templates>
    <Stylesheets></Stylesheets>
    <Macros />
    <DictionaryItems>
      <DictionaryItem Key="PublicationModule">
        <Value LanguageId="1" LanguageCultureAlias="en-US">
          <![CDATA[Testing]]>
        </Value>
        <DictionaryItem Key="PublicationModule-Title">
          <Value LanguageId="1" LanguageCultureAlias="en-US">
            <![CDATA[Publication module]]>
          </Value>
        </DictionaryItem>
      </DictionaryItem>
      <DictionaryItem Key="NewsModule">
        <Value LanguageId="1" LanguageCultureAlias="en-US">
          <![CDATA[Testing]]>
        </Value>
        <DictionaryItem Key="NewsModule-Title">
          <Value LanguageId="1" LanguageCultureAlias="en-US">
            <![CDATA[News module]]>
          </Value>
        </DictionaryItem>
      </DictionaryItem>
    </DictionaryItems>
    <Languages />
    <Actions></Actions>
    <DataTypes></DataTypes>
    <control></control>
</umbPackage>

AppendXmlTask.cs

using System.IO;
using System.Xml;
using NAnt.Core;
using 
NAnt.Core.Attributes;

namespace CPalm.NantTasks
{
    /// 
<summary>
    /// Appends nodes from a source xml document to a
 target xml document
    /// </summary>
    
[TaskName("appendxml")]
    public class AppendXmlTask : Task
    {
       
 [TaskAttribute("sourcefile", Required = true)]
        
[StringValidator(AllowEmpty = false)]
        public string 
SourceFile { get; set; }

        [TaskAttribute("sourcexpath", 
Required = true)]
        [StringValidator(AllowEmpty = false)]
       
 public string SourceXPath { get; set; }

        
[TaskAttribute("targetfile", Required = true)]
        
[StringValidator(AllowEmpty = false)]
        public string 
Targetfile { get; set; }

        [TaskAttribute("targetxpath", 
Required = true)]
        [StringValidator(AllowEmpty = false)]
       
 public string TargetXPath { get; set; }

        protected 
override void ExecuteTask()
        {
            //Check the file
 exists
            string sourceDocPath = 
Project.ExpandProperties(SourceFile, Location);
            if 
(File.Exists(sourceDocPath) == false)
            {
               
 throw new BuildException("The sourcefile specified does not exist");
           
 }

            string targetDocPath = 
Project.ExpandProperties(Targetfile, Location);
            if 
(File.Exists(targetDocPath) == false)
            {
               
 throw new BuildException("The targetfile specified does not exist");
           
 }

            XmlDocument sourceDoc = new XmlDocument();
           
 FileStream fsSourceRead = new FileStream(sourceDocPath, FileMode.Open, 
FileAccess.Read, FileShare.Read);
            
sourceDoc.Load(fsSourceRead);
            fsSourceRead.Dispose();

           
 XmlNodeList sourceNodes = sourceDoc.SelectNodes(SourceXPath);
           
 if (sourceNodes.Count < 1)
            {
                
Project.Log(Level.Warning, "No nodes found via XPath in source file!");
           
 }
            else
            {
                
Project.Log(Level.Info, string.Format("Found {0} nodes in source file 
via XPath", sourceNodes.Count));

                XmlDocument 
targetDoc = new XmlDocument();
                FileStream 
fsTargetRead = new FileStream(targetDocPath, FileMode.Open, 
FileAccess.Read, FileShare.Read);
                
targetDoc.Load(fsTargetRead);
                fsTargetRead.Dispose();

               
 XmlNodeList targetNodes = targetDoc.SelectNodes(TargetXPath);
               
 if (targetNodes.Count < 0)
                {
                   
 Project.Log(Level.Warning, "No target node found via XPath in target 
file!");
                }
                else if 
(targetNodes.Count > 1)
                {
                    
Project.Log(Level.Warning, string.Format("{0} nodes found when trying to
 find one target node found via XPath in target file!", 
targetNodes.Count));
                }
                else
               
 {
                    XmlNode targetNode = targetNodes[0];
                   
 foreach (XmlNode sourceNode in sourceNodes)
                    {
                       
 XmlNode newNode = targetDoc.ImportNode(sourceNode, true);
                       
 targetNode.AppendChild(newNode);
                    }

                   
 FileStream fsWrite = new FileStream(targetDocPath, FileMode.Truncate, 
FileAccess.Write, FileShare.ReadWrite);
                    try
                   
 {
                        targetDoc.Save(fsWrite);
                   
 }
                    finally
                    {
                       
 fsWrite.Dispose();
                    }
                    
Project.Log(Level.Info, "New nodes imported");
                }
           
 }
        }
    }
}