If you haven't already, you need to read Hervey's blog entry on Namespaces. Short summary: the namespace for WSE 2.0 has changed from Microsoft.Web.Services to Microsoft.Web.Services2 ... note the all important “2” at the end of the namespace. This applies to the name of the assembly as well.
For me, it means revisiting all of my code for the MSMQ transport provider and updating it to reflect this change in namespace. If you've been playing with the Tech Preview, thischange reinforces why it was a Tech Preview. It also means don't plan on bringing WSE 1.0 code seamlessly forward into WSE 2.0.