Took me awhile, but I was able to piece together MAMEHooker and Troubleshooter 2 to get the M2 emulator to send 'outputs'. I'm using an Ultimarc Pac-Drive controller.
I've got outputs for VR buttons 1 through 4, and the Race Leader Lamp (although I don't have an actual light hooked up to the race leader light yet...).
I used the scripts found here by Boomslang :
http://forum.arcadecontrols.com/index.php/topic,155698.0.html (Thank you for everyone hard work on putting this all together)
I don't seem to have an output identified for the round start button. On the real machines the round start button seems to blink continuously in attract mode. Can also been seen on Boomslang's cabinet. (see videos below)
There is a "coin_chute 1" output that trips when you enter a coin, but that doesn't seem to be it.
Maybe I'm not seeing the 'output' as my configuration isn't in 'free play' mode, and that only blinks in free play?