In theory it should be possible if it's running those buttons through those pins on the connector, I'd see if I could get my hands on a pinout of it to confirm before trying, as it could get messy if that's not what's going on. If all else fails, might want to check with Koumphon from
http://forums.arcade-museum.com/showthread.php?t=91052 looks like he was having some wiring issues so may know how that one works. I know Time Killers and BloodStorm use the 2 leads next to button 1-3 for 5 buttons per player and the NC's closer to the power section of the jamma finger for stereo speakers. Theoretically the blue elf could be using that one for the 6th button instead of the ground lead down on the end. I'm actually in process doing pretty much the opposite of your situation, I have a bloodstorm with the 4 and 5 buttons wired into those n/c's and I'm going to be wiring the kick harness from a MK into the right spots using one of the finger boards from jammaboards. Ultimately it's just a matter of wires going to buttons, if there's open leads you can use them in the harness, just make sure that the pin isn't being used by something else before you wire it up.
*e* and if that board works well, let me know, I was looking at that one as a possible drop into a cabinet, but I don't want to lay out the cash if the performance is sketchy.