Using L-SHIFT as a normal key, not a modifier?

[Guest floyd1212]

I would like to use the L-SHIFT as a normal key instead of a modifier. (Yes, I realize this is probably a major sin in some people's eyes.) Anyway, I can successfully remove the key from the modifiers list, and assign it to a function in the controls menu, but when I fly, the key does nothing. Should this be possible, or are certain keys not usable?