Custom Test Types Visual Studio 2012

Hello,

Currently I'm trying to write a custom test type for Visual Studio 2012 using the VS 2012 SDK. But I can't find any good reference material about this (also not for VS 2010).

Does anyone now any good references? Until now I found the following:

http://msdn.microsoft.com/en-us/library/bb166484(v=vs.90).aspxbut this doesn't help me with the implementation...

Thanks in advance