When I ordered my S5, I had test driven an '08. The sideview mirrors folded in automatically. The manual for my '09 shows the switch should be on the door panel but it is NOT there. Did they remove this for '09?
This question has been asked several times recently. No one seems to know the answer yet why Audi removed the folding mirrors from US spec '09 A5/S5s. Interestingly, folks in the UK (and probably some other countries) are still able to get them.
FYI, here are a couple of the threads where this topic has been discussed: