well first off you cant use your derailleur with a setup like that. Dimension Edge and Staton have both done what you are trien to get done. I am the son of the owner of Dimension EDGE and know first hand how dangerous running an engine through your derailleur can be. I dont have the time to explain how it all happens but your derailluer will end up in your spokes if you keep it the way it is... our fix for that situation is just using an internal shifting hub.

Sorry i couldnt go into more depth but i posted this at work so gotta go.