Sometimes it takes a second, especially for the trunk lid, I usually push the button a few times. Try unlocking the door, then (with all doors closed) touch those ridges of the picture above, if the door locks then thats a good sign. To unlock it, all i do is lightly touch the inside of the door handle and it unlocks all the doors. You should look around idrive too, cause I'm pretty sure I saw a menu option for something to do with comfort access, or what doors unlock, something like that.