NumPad Workaround in Leopard?

The new MacBooks have lost the NumPad option and I really do need to use it. I do not have to have to get an additional keyboard to use just the NumPad as it defeats having a portable computer. Does anybody know of a command work around or any third-party applications that I could use in place? I know Windows has a virtual keyboard where you can click on the keys with your mouse; is there anything like that for Leopard where a NumPad is displayed that I could click on?

I use a program that switches menus based on the NumPad entry and there seems to be no other option if I'm to access this. Thanks for any suggestions.

 

Any tips of how to go about with that? I tried to create any type of shortcut key, but since I couldn't find any command for or way to reference the NumPad numbers, I wasn't able to.