Enabling typemock on a TFS build server via PowerShell

I know we have to use the typemock.tfs2013.dll and it contained activities to enable Typemock mock within a TFS build.

As TFS 2013 now has a PowerShell hook before and after the test step would it be possible to replace these activities with a PowerShell script?

I tried writing my own (attached) which as the same logic as is contained in your DLL, but they don't seem to work. They load without errors, seem to set the correct environment variable, but any mock test fails as if the runner is not running.

Any idea why this may be. It is just a PowerShell based way of enabling seems easier to manage for all

TMtest1.ps1.txt