visual studio/blend and mvvm

hello,

i been working with wpf and mvvm for a while now.

up until now i created the view model class and in the code behind of the window i wrote:

this.DataContext= m_mainPageVM;

and it all worked fine, however if i want to make my life easier, for example by setting a data binding through visual studio properties panel i cant find my vm there,
so i have to write the binding text manually.

so i tried adding a Data source through the visual studio DataSource panel, in there i can find the Vm class but when i try to bind something to it, it just dosen't work...

so i guess what i'm asking is:
what is the best way to work with the designer and mvvm?

thank you very much in advance