APM 2.6/7: Tricopter: Can't modify tail servo throw

ArduCopter Copter 3.2
1

Digital servo. Connected to tail tilt assembly. Of course native throw is too much, need to restrict it.

Advanced settings, RC7 (output, not input) min / center / max rewritten, sent to APM. Tried with APM Planner and Mission Planner. Same result. Tried many different values, of course centering around 1500, but servo throw does not change. Only thing that works is reversing the servo.

Really annoying, can’t fly like this. Anyone else with this issue? Any solutions?

Thanks.

(Using HobbyKing APM 2.6/2.7.)