There's a new version of the Visual Studio SDK available (supporting VSTS RTM)

 
For more information. There should also be updates in there for VSTS matching the RTM version. I hope they have done more than only upgrading, because some more detailed documentation would be very helpful.
 
Download it here: http://msdn.microsoft.com/vstudio/extend/ (and choose the april version)
 
You will need a VSIP login however, but registration is free.