I cannot get the combination of Command + any function key to work in 5.0.1. I am running a Swedish Mac OS X Tiger.
Combining the command key with for example shift works though. So for example, File Structure Popup does not work with the default Command-F12, but does work with Command-Alt-F12.
I might point out that I have unmapped all Exposé stuff and set the keyboard settings to allow for applications to use the function keys.