Is it possible to use build Windows Phone projects using Team Foundation Service's hosted build agents?

I'm trying to get a solution containing a Windows Phone app to build on check-in to Team foundation Service (i.e. the hosted service), however it is failing with errors like:

C:\Program Files (x86)\MSBuild\Microsoft\Silverlight for Phone\v4.0\Microsoft.Silverlight.Common.targets (200): The "CompileXaml" task failed unexpectedly. System.IO.FileLoadException: Could not load file or assembly 'PresentationCore, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047) File name: 'PresentationCore, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'

Is it just the case that Windows Phone apps aren't supported for builds, or do I need to apply some magic to the build template?

If you are using the Windows Phone 8 SDK, then you should be good to go according to the current list of software that is installed on the hosted build servers on the Team Foundation Service: http://tfs.visualstudio.com/en-us/learn/hosted-build-controller-in-vs.aspx#software.