Well, as explained
here, buttons are not binded to specific keys like 'x' or 'h' or 'space' or 'shift' or whatever. So for what you want... you'd have to make a whole new action thing, which definitely can't be done in LUA.
But maybe there is a function to see if a certain key is pressed, rather than a game button. Like IsKeyPressed instead of IsButtonPressed (That's not a real function but just for example of what it could maybe be). Hooking into the game could work too, as then you could use whatever code you wanted, not just Bully LUA, to get what keys are pressed. But don't ask how hooking works.. because it's a big explanation and I can't teach you. Here's a wikipedia page if you really wanna give it a shot:
Hooking.
