After some tests and after receiving some feedback, Andrea Boschin decided to revisit his Inject ApplicationServices with
MEF post.
Source: Silverlight Playground
In my last post about injection of ApplicationServices with MEF I've presented a simple solution that allows people to adds instances of ApplicationServices, without the need of adding the markup to the App.xaml file. The solution was interesting as a demonstration of how MEF works, but after some tests and some feedbacks I had I realized it is not applicable in a real world solution because of a subtle problem.