international keyboard: Best way to use as3 keycodes

hello there, on Adobe's documentation you can find some info about as3 keycodes (most used keys to control game) I asking myself, about international keys on non standard keyboard, what about those keys that doesn't has keycode? I never see many global keyboards, but maybe you can find a lot...,

Extending a class? with constants? some class on internet? Where can I find info?

What's best way to capture those "unknown" codes?

http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/ui/Keyboard.html

best regards