no rewire
you need an usb joy and the ENTIRE PIU ARCADE dancepad, in order to use the JAMMA connector to make the modification.
here a picture explaining the JAMMA circuit:

this diagram is not perfect to make piu modifications, but helps ;D because JAMMA is for arcade dedicabs like street fighter, neo geo ..you know)
the UP DOWN LEFT RIGHT AND BUTTON 1 = 5 inputs for player (depending the JAMMA side)
the other side is exactly the same
dont worry about wire order...., you can wire in any signal point because the game can be remapped in options mode, otherwise in your joy2key favorite software.
the coin, service and test are the same in a PIU Cabinet. (because JAMMA is a wiring RULE for arcade systems)
the final result must look like this:

homemade board used to make workable STEPMANIA into a PIU cabinet.
tip: in order to JAMMA pinout, make sure you have connected a +12v wire (yellow power wire) from computer... because the I/O boards inside each dancepad needs power to work.
cya