Got it working. Although, it only shows three of the five MP3s that I loaded onto a separate USB stick. There's a discussion over on Reddit about the need for a second USB stick and removing the spaces in the file name to get everything to show up. Still playing around with it.
MelGeek - your idea is the best I've found so far. Got that working and it sounds awesome
I didn't realize initially that you have to use the same sound for forward and reverse. Too bad we can't customize those to be different. Oh well, still awesome!