The turn control actually worked with attitude hold in a previous version, but somehow I managed to screw it up in the 4.1 release. Oh well.
The FSX wing leveler has always been a headache as it is inherent in the attitude and altitude hold functions unless you disable it in your gauge functions and set the fly_by_wire attribute in aircraft.cfg explicitly to zero.
Your solution is OK although it may conflict with some other parts of the system. Thanks for your input, I will try to work it from there.
BTW, please use the “code” tag when adding code snippets in your posts.