JetBrains just has released ReSharper 4.0 (R#) final after the first release candidate one week. For the new features of this version, you can check it here.
The sad thing is R# 4 didn't do full support for XAML. I can see a lot of errors and warnings when I open a XAML file. Hope that they will resolve it in one of the next versions soon.
Anyway, I will try to find a workaround for this problem. And I can find it, I will post it here.