Visual Studio Shell and VSPackage of WPF

I need to create a Visual Studio Shell with a custom WPF project template.
I follow the link:
Walkthrough: Part 1 - Creating a Basic Project System (http://msdn.microsoft.com/en-s/library/cc512961%28v=vs.110%29.aspx)
Walkthrough: Part 2 - Creating a Basic Project System (http://msdn.microsoft.com/en-us/library/cc826178.aspx)

I explain my problem. I open in designer the xaml but when i build and execute my VS shell i try to load the new WPF custom template: The new project is loaded with reference and .cs files but the xaml no, without exception.