T4 template for EF POCO Code generator is not a part of the vs2010 beta 2 ,it was part of Microsoft ADO.NET Entity Framework Feature Community Technology Preview 1.
Hence to use it either u have to use the old preview and .net beta 1 instead of .net framework beta 2 .
If you have already installed .Net framework Beta 2 ,then the t4 template you can use is Templates for Self-Tracking Entities by installing
Microsoft ADO.NET Entity Framework Feature Community Technology Preview 2
