Hi @bresch,
Inverting the signs of the output scalings in the wingwing.main.mix file and rebuilding the firmware corrected the roll backward behavior in stabilized mode. Thanks!
O: -10000 -10000 0 -10000 10000
@Al_B , @rollys Here it is : https://ufile.io/5nf50
I used 1.8.0, not the rc0, that was a mistake.
@Al_B In my version, I didn’t invert the output but just the roll axis, but good to hear that it works now! 
Hi there, I am having the same problem but wit the pitch axis. In stabilise mode the roll axis counteracts correctly but the pitch is reversed. How would I go about solving this?
Same as said before: reverse the sign of the outputs and swap left and right servo connectors.
How do I reverse the sign of the outputs?