MS Natural Keyboard 4000/Vista: Hotkey to open/close optical drive

Is there a program/script that can be linked to in Windows Vista via the
Microsoft Natural Keyboard 4000's 5 hotkeys that will open and close the
optical drive?

I have an HP a6000n, and I know that the keyboard that came with it has a
dedicated button for this purpose.

I'm looking for a directory tree/link to the program in question that opens
AND closes the tray, or a suggestion for a utility that does this, if none
exists in Vista.

Thanks.