Well, it's not "wrong". It's just not recommended. If you insist on calling the ObjectContext directly, use it sparingly since if you're using it too much, that'll defeat the purpose of having DevForce.
You can create your own ObjectContext by passing in the ClientEdmKey.ConnectionString to its constructor.
However, before you do so, I'm really curious as to the original problem. What exactly is the exception you're getting? Do you get the exception when you try to map the Dynamic SQL StoredProc to your edmx?