Redefining mod key?

[TrueProphet]

Is it possible to redefine the mod key?

I'm using OS X, and trying to trim a plane in flight. Only problem is, that the key shortcut alt-s is instead triggering a Steam shortcut. (I'm also hitting issues with alt-f-number keys instead triggering OS X functions, but that's less significant). Changing the mod key from alt to cmd would solve this, but doesn't seem to be an option within the KSP settings. Any ideas would be appreciated.

Edited May 5, 2015 by TrueProphet

[Rhomphaia]

You could manually edit settings.cfg

search for

MODIFIER_KEY

[TrueProphet]

Perfect - thank you. For anyone else with the same issue, the full path is ~/Library/Application Support/Steam/common/Kerbal Space Program/settings.cfg and the description to use for the command keys are LeftApple and RightApple