After fixing the problem above using the unlocking procedure from http://www.bmwe34.net/E34main/Trouble/Locked.htm
I succeded to get into the car, but the left door is not usable anymore.

First I try this procedure on the left door. I heard the "click" when turning the key to the left, the door didn't open and the key didn't move to the right anymore.

The right door worked like a charm, but now I cannot use the central locking of the car from neither key or alarm remote. Basically I can't lock the door anymore.
Is this related to the synchronization procedure? Did I miss something?