Hey, just wanted to share my findings. For some reason, Joiplay doesn't recognise alt and shift. However, if you change those buttons to anything normal like numbers or letters it works without any issue. I changed speed-up from alt to Z and the fast forward button works (just remember to unbind from "action" so that Z doesn't have both functions as it won't work). Same with registered - changed from shift to 1 and it works perfectly, you can rearrange your backpack and use key items. It probably rotates the puzzle in circus as well.
BTW, you can also enable debug mode if needed. J