Update Xml File (vsixmanifest)

I'm creating a Visual Studio 2013 Package (vsix) (shameless plug: pMixins ). As part of my quest to use TeamCity as a continuous integration server, I have configured Team City to build the .vsix Package (Visual Studio Package (vsix) - Team City without Visual Studio installed).

Now I want to configure Team City to set the Version in the VSIX Schema:

<?xml version="1.0" encoding="utf-8"?>
<PackageManifest 
    Version="2.0.0" 
    xmlns="http://schemas.microsoft.com/developer/vsx-schema/2011" 
    xmlns:d="http://schemas.microsoft.com/developer/vsx-schema-design/2011">
    <Metadata>
        <Identity  Version="1.0" Language="en-US" Publisher="Company" />

Following the advice in Using msbuild I want to update a config file with values from teamcity and How do I update an XML attribute from an MSBuild script? I have updated Microsoft.VsSDK.targets to use XmlPoke with the following Target:

<Target 
     Name="UpdateVSIXVersion" 
     BeforeTargets="PrepareForBuild" 
     Condition="$(VSIXVersion) != '' And $(VSIXVersion) != '*Undefined*'">

    <Message Text= "Updating VSIX Version" />

    <XmlPoke 
        XmlInputPath="source.extension.vsixmanifest"
        Query="/PackageManifest/Metadata/Identity/@Version"
        Value="$(VSIXVersion)">         
    </XmlPoke>      
 </Target>

I updated Team City with a system Parameter to set VSIXVersion:

But, when I check TeamCity, it made 0 replacements:

How do I get Team City to correctly update the .vsixmanifest xml?

After much searching I finally found the XmlPoke expects a namespace when the Xml file contains a namespace, even for the default namespace (Modifying .config File in an MSBuild Project).

However, I couldn't find any documentation for the XmlPoke.Namespaces parameter and the above referenced code didn't work. After much trial an error, I finally got it to work with this:

<Target 
    Name="UpdateVSIXVersion" 
    BeforeTargets="PrepareForBuild" 
    Condition="$(VSIXVersion) != '' And $(VSIXVersion) != '*Undefined*'">

    <Message Text= "Updating VSIX Version" />

    <XmlPoke 
        XmlInputPath="source.extension.vsixmanifest"
        Query="/n:PackageManifest/n:Metadata/n:Identity/@Version"
        Value="$(VSIXVersion)"
        Namespaces="&lt;Namespace Prefix='n' Uri='http://schemas.microsoft.com/developer/vsx-schema/2011' Name='DoNotKnowWhatThisIsFor-ButItIsRequired' /&gt;">
    </XmlPoke>

Notes:

This requires MSBuild 12 to be configured on Team City
The Namespaces needs to be escaped.
The Name parameter is required, otherwise MSBuild will error out
The original XPath query had to be updated with the artificial namespace prefix.

MSBuild file is on Github if anyone needs it: https://github.com/ppittle/pMixins/blob/master/tools/vssdk_tools/v12.0/VSSDK/Microsoft.VsSDK.targets