Well no luck. I installed Silktest 2006 R2, and tried to get the declarations from a WPI application. I could only see the Frame that hosts the application. Nothing else was seen. No menu's, no buttons, no nothin!
I sent an email to out Silktest Rep. So if i hear anything i'll let ya know.
I dont know the answer, but in general, tool vendors lag about a year behind. So, since WPF was released a few months ago, I would bet that most tools don't support it yet (or anything else specific to .NET 3.0).