You have to have the wing mirror knob set to L for it to do it automatically.
Well, the thread's been some use anyway.
I sort of knew it was supposed to do that, but Kev's right, there are a lot of cool little details you don't necessarily take in when you're going over the specs. I haven't noticed my mirrors do that, and this must be the reason. I have to leave the knob on L or it won't happen.
You learn something new and (slightly) useful every day.
Next tip, if you're relying on rain and the automatic wipers to keep the winscreen clear, the headlamp washers won't be activated and the headlights may be a lot dirtier than you think. Wash your windscreen now and again even if it doesn't really need it to keep those searchlight beams in tip-top condition.
Rolfe.