MVVM and who should invoke RemoteServerMethod?

I am trying to figure out which class should invoke the RemoteServerMethod? I first thought of the ViewModel but the InvokeServerMethodAsync is called using the EntityManager. My ViewModel doesn't have any knowledge to the entitymanager as my viewmodel calls the repository who calls the various CRUD methods. So I am thinking that the ViewModel should call the Repository and pass over the methodname and typename and let the repository call the invokeServerMethodAsync unless there is another approach or I am missing something. On the other hand this is not really a method for the repository because inside the remoteservermethod I make CRUD calls but since the repository class is the only class that knows of the entitymanager I can't think of any better way to do it.

Bill