Aaaargh! I think I'm going mad.

I've followed the instructions to the letter, but still I cannot get the mirrors to automatically adjust when I have the mirror in R and in reverse gear. It doesn't happen. Can anyone who has it working telling me what's missing from the instructions?

Storing exterior mirror setting for reversing
– Switch on the ignition.
– Turn the exterior mirror control to position R ⇒ page 57.
– Engage reverse gear.
– Move the right exterior mirror into the desired position ⇒ page 57.
– Take the vehicle out of gear. The set position of the exterior mirror is stored.