+2  A: 

The answer to your questions are, respectively:

  1. Yes.
  2. See (1).

The Entity Framework allows you to insert/update/delete via DML or stored procs, but it does not allow you to choose "both." If you are going to go to the stored proc route, you must supply procs for every sort of data modification the framework might need to do on an entity, including relation tables.

Craig Stuntz