Environment Variable for AppData\Local / Access Downloaded custom assemblies

I am trying to setup my TFS2010 Build and I want to access the files that are downloaded via the "Version control path to custom assemblies".

From what I can tell those files are downloaded to:

C:\User\\AppData\Local\BuildAgent\

I can directly access that folder via the above path, but it would be nice if there was an environment variable (or something I can use in the build) to access that folder indirectly.

Or... Is there a better way to get at these files? (I am putting a version file in there to be downloaded every time the build is run).