I ran into this annoying issue when I was finally setting up my keyboard shortcuts for JSFL’s in Flash CS4. I always use cmd+opt+shift+[...], but unfortunately on a mac, when you throw the option key in the mix, Flash uses the unicode characters that are mapped to whichever key you press. Not all keys on the mac keyboard have a unicode character mapped to them, so for example, cmd+opt+shift+U works fine, but other keys don’t work so hot.