FMS doesn't know the difference between a plane with a tail, and a flying wing. As far as the program is concerned it is all the same. Set your left/right joystick axis to ailerons, and your up/down axis to elevator. Check off inv on any channel that is doing the opposite of what you expect (if moving the stick right rolls you left, or pulling back noses you down).
I guess the exp is like the exponential function on some transmitters, this can help reduce the sensitivity at low movements, yet keep the full movement there if you move the stick all the way.
Hope that helps.
Try my "Zagi" models