Using the program at the following URL:http://www.shellfront.org/utils/scankey.zip
You can find that the ScanCode for the MediaDirect button is 000000FF.
I'm using the LiteStep shell, so I can go into the hotkey configuration file and switch the FF code to whichever application I want. I don't know how to do that with explorer. Maybe Dell Quickset has something to say about this?