How to get the TFS changeset for a build.

TFSChangeset.msbuild

<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <AssemblyFile>.\packages\MSBuild.Extension.Pack.1.3.0\tools\net40\MSBuild.ExtensionPack.TaskFactory.PowerShell.dll</AssemblyFile>
  </PropertyGroup>

  <UsingTask TaskFactory="PowershellTaskFactory" TaskName="Changeset" AssemblyFile="$(AssemblyFile)">
    <ParameterGroup>
      <changeset Output="true" />
    </ParameterGroup>
    <Task>
      <![CDATA[ 
      $tf = & "C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\tf.exe" history . /r /noprompt /stopafter:1 /version:W
      $changeset=$tf[2].Split(" ")[0]
      ]]>
    </Task>
  </UsingTask>

  <Target Name="Build">
    <Changeset>
      <Output TaskParameter="changeset" PropertyName="changeset" />
    </Changeset>
    <Message Importance="High" Text="Changeset $(changeset)" />
  </Target>
</Project>

I was trying to get TFS and teambuild to use the TFS changeset as its versioning scheme, well the hack above gets you the changeset. But you cant set your build number to reflect it (In teambuild) so it not much cop is it? (I mean we knew that already but....)
Another reason to use Teamcity.