Hotkey Label Formatting Question

[Cybane]

Okay when you want to bind a hotkey using Ctrl or Alt it will shorten it to C or A. Now I use my number pad and would like to be able to do the same thing. Either shorten it to NP or just N however, I can't seem to find the file that controls those changes. Which file controls how the labels are actually displayed on the hotkey themselves.

Thank you