How do you adjust the headrest on a 2002 745i BMW?

The 02 standard seats have the headrest movement linked to the forward/reverse movement of the seat. I was not going to buy the car because of this ill-conceived "feature". It assumes if the seat is moved back the passenger is a tall person and adjusts the headrest up accordingly. Move it forward and it lowers for a smaller person. There IS an undocumented defeat switch of some sort under the seat that only one person in the service dept at my dealer knew was there and how to operate it. What ever he did (it took 3 minutes) the headrest no longer moves with the seat. You can manually move it up and down however. If your service person can't figure it out tell him to contact BMWNA.