Airtronics m11x and Traxxas Summit

[claytrackstar]

Hello all!
Finally killed the stock radio in my Traxxas Summit. I have a 4 channel receiver for my m11x. I have decided that I would like to run the diff lock and the gear selector from the 3rd and 4th channels of the m11x radio. Does anyone have experience with radio settings that will make this possible? I'm having a hard time figuring out how to program these channels and mapping them to a switch or button on my radio. Any advice or people out there with a ton of experience with the m11x? Help! I want to drive! lol thanks a bunch guys!