Is numlock supported on mac os 10.5? I have the latest build (not sure with one it is) and I can't figure out how to get the number pad on my keyboard working.
P.S. I tried Parallels, Fusion and Crossover and I VirtualBox is simply amazing for the price
Although this solution isn't free, it is fairly cheap. You could try using an external USB numeric keypad. The guest computer should recognize this natively and it should work fine for you (as long as VBox likes the device anyway, there are a few USB bugs too).