I know on My 09 mustang I have the same button. there is a module from Ford that will upgrade it but it is $600 for the module and then the computer in the car has to be reprogrammed by Ford )more money). I was told that there was a change mid 2008 and if you have an earlier 08 one it won't work. not sure if Expeditions are the same.
my 08 required a MobileEase installation to use a Bluetooth phone - had it installed at CarToys when the Expy was new - it was a few hundred bucks to buy and install
small device installed on dash next to the 4wd selector and a mic attached above the rear view mirror
works great but wish it had a display (maybe it does by now)