Opti-Pac what can I do about hooking up coin ?

[mrclean]

I got an OptiPac from Ultimarc, It was intended to be used for just two trackballs, two start buttons, and coin(s). Everything is working as it should except (kind of) out of inputs / can't flash or program anything as it's not compatible with ultimarcs software.

The bottom of the ultimarc OptiPac shows LEFT / RIGHT respectively as I can use those as the player 1 and player 2 start buttons although they are right click and left click on the mouse which can still get mapped to TAB / using MAME... However I have many free spaces on the ultimarc OptiPac yet I can't use any of those inputs because I can't flash / reflash the say spinner x y (which is unused) to whatever I want. Any Ideas on how I can use literally just one more input on this with the restrictions it has of not being able to use ultimarcs software ? MAME won't recognize those other spin / inputs.