I am working on converting my Rush 2049 cabinets into emulation cabinets with a PC in them and I just got the keypad working. It shows up as 12 raw inputs, raw 17 - raw 28.
For each game I want to use it in I'll have to map it to specific buttons/keys for that game.
In this video below I am running Project R and have mapped the buttons to the numbers, numpad multiply for the *, and Enter for the # key.