John, first to have two servos on different channels on the rx you have to set up a mix where say left servo is master (channel # x), and right servo is slaved (channel #Y)

Then you would need to set two additional mixes, controlled by a switch on the tx to turn them on and off if need be.
One mix would be left aileron master, left elevator slave. Second mix would be right aileron master, right elevator slave.

The manual will explain how to do it and assign both of these mixes to a single switch. The first mix is set up with no switch, and set to be always on.

You may have to play with the mix ratios as if the elevator is too aggressive it may make it oscillate as it rolls, ditto if it's to weak. As you are going to be using four surfaces to rotate the fuse on one axis.