I have a DJI F550 in hexa X configuration. It was flying perfectly with the Naza controls using a Turnigy 9XR with FrSky DJT transmitter and FrSky D8R-IIplus. I recently upgraded to the Pixhawk and am having some problems.
I flashed the D8R with the XP firmware to get CPPM functionality, and that seems to be working fine. When I press forward on the pitch stick, the APM software pitch display increases. When I pull back on it, it decreases. But when I try to fly the copter, when I pitch the controls forwards, the copter tilts back at me - and vice versa.
Of course I have checked to make sure that my motor numbering matches the APM documentation and that the Pixhawk is pointed towards the front of the copter.