Swedzilla, did you manage to sort it out?
I have the same problem since a few weeks back. Mine just started out of the blue doing this, no cold weather, snow, ice, wet... just a summer day. Its like the stopping mechanism has moved from its normal ~90 degree position way forward.
It folds back in nicely all the way but then folds itself all the way out when I try resetting it.
One strange thing which annoys me the most now is that about 1/3 of the times I hop in the car and start it the mirror then folds itself towards the front from the normal position sort of to seek the locking mechanism thats sitting out of place.
Have read threads about this problem on the forum, have tried to stop it manually etc without success.