Have you tried contacting a BMW dealer to check if the car was supplied with folding mirrors, as in the UK many X5's do not have folding mirrors. Possible someone has just added the switch at a later date, because a window switch had broken.

With the how to link you will see the microswitches when you take the mirror covers off, if you do not have them you will know that your car was supplied without folding mirrors.

My mirrors folded in then out and did not stop in the folded position.

Phill