Steve, Do you have memory seats? My Turbo had them and this feature only worked if you programmed it wth the seat feature. Check your manual under the memory seat functions?
I seem to recall that you activate the "mirror-dipping" by setting the seat memory while the car is in reverse. I don't know what you do if you have manual seats. I know that I had to look it up in the owner's manual so the non-memory seat process should be in there as well.