View the Entity Spaces 2008 blog about their new developments.  They are adding the ability to generate ES frameworks directly within Visual Studio.

From the ES Blog:

We are very excited about our upcoming CodeSmith support for ES2008 and will post more as soon as we are generating a complete EntitySpaces based application from within Visual Studio.

I personally have always felt that the need for the myGeneration standalone generator for Entity Spaces was problematic.  It felt totally out of place from within the rest of the ES product.  I am very happy to see them moving towards a more developer friendly generation system within Visual Studio.