I know on the Expeditions there is a location that the master code is stamped in the interior, look in the owners manual for the location. With that code you can re-program it to whatever you want to use.
Where did you end up finding the code at? Got a guy at work that is trying to reset his and he has no owners manual. Before we go tearing the interior apart we would like to have some clue as to where to look for it.
I got mine I just bought 05 take the tray out the one to the right of sterring column, lift up the white heat sheild padding, there is the computer is the keyless enrty code is on a white sticker..write down the code worked perfect...
I've been wondering if this was possible for my wife's Expedition (she bought it used) looks as if I have something to do when I get home. And at least I have the owners manual.