Volume key as modifier?

[tradej]

Hi, first of all, many thanks for the great port, I'd never say such a thing is even possible.

As Duke uses quite a few keys, there are some IMO important keys unmapped at the moment. I was wondering whether it it possible to map the Volume key as a sort of modifier that would enable more key presses, like:

• Volume + Start: Crouch
• Volume + Select: Next weapon
• Volume + A: Use inventory
• Volume + B: Next inventory

Thank you.