New Post: ViewModel injection

Using Prism 5 with MEF (Framework 4.5.2).
In 2 different modules I want to use the same view, but with different ViewModels.
I cannot figure out how to do this without hardcoding View and ViewModel instantiation, then setting View's DataContext before registering with RegionManager.
Any hints on this ?

Also I would like (I think) to use ViewModel-first with MEF, but cannot figure out how.