2 days later, I really can say this is working the way I wanted it to. Just a problem with HyperSpin related to gamepads in general, but JoyToKey solved the problem once and for all. Problem is the same with all gamepads, so no way to blame the Picade.
Just in love with my bartop :)
I promised Mark a full review when everything is done to help in case anyone would be crazy enough to do the same. And I'll do it. Still waiting for my new shrim, marquee and control panel to be printed, and also some new buttons I ordered at Arcadeworlduk, but with SF V release, orders are just taking a little bit more of time.