If this is possible, you probally will have to take the serial route.
Can you think of any way to figure out what each pin does? Where do they lead to? Is that screen in the pic hooked to this in any way?
Try hooking up a multimeter (set to condinuity) to each pin and a ground, and pressing each button to see if it jumps. If you can work out some sort of pattern with this, you may be able to use a digitol input card.