Need help with analog handbrake

Hi, i recently got horizon 4 im using a g27 wheel with a custom handbrake made with a arduino micro it works fine in assetto corsa but in horizon it works with some cars but most of the cars wont even moves with the handbrake plugged in

its well calibrated. Ive tried joytokey but forza wont let you use keyboad input and the wheel at the same time so when i pull i cant turn my wheel which is a major handicap

So im looking for a way to make it work i was looking for a way to turn the axis into a on/off switch or a app like joytokey that would let me map my handbrake to the wheel button, maybe my arduino settings arent right

Thanks