Flaperon Setup
When using flaperon mixing, two servos (one
for each aileron) must be used. Connect the
left aileron servo to channel #6 (Flp/Aux 1) and
the right aileron servo to channel #2 (Aile) in
the receiver. Individual functions (e.g., servo
reversing, sub-trims, etc.) are still available
for each of the channels. Use sub-trims for
individual neutral adjustment.
Note: When flaperon is selected, it is
necessary to reduce the travel adjust
values of channel #6 0% in each direction
to prevent servo over-travel (binding).
Please refer to section 7.3 for travel adjust

This is more of the manuel and tells more about it. I may have copyed the wrong second before.

sticks