Gday, and welcome to the forum. Good to see another Aussie on here. Ive seen numeric num pads at Dick Smith electronics, that just plug into the PS2 port. No need to worrk about a hack cause its all done., the PC just thinks its a keyboard.
Im going into the city in a few days, I can check it out for you if you like, if you dont have a Dick Smiths's where you live. Hope this helps, cheers . . .