SS in order to forward calls to cell phone don't you have to have Auto ATT. parameters set to external? Other wise it just notifies you of messages right?

if you have set to external you dont get AA.
The easiest way is to call forward your phone external (with sys spdial) leave the AA set for internal this way it will pull call back and take a message if you donot answer. You need to set day/night no answer and busy. Remember the follow me of the mailbow is really just for notification not for forwarding.