The trim you want to remove is the bit of plastic behind the mirror. It is held on by three clips which are slid into the trim by the head and then pop into the holes in the door by their tails.
To remove, push the piece of trim upwards to slide it off the heads of the clips. Pull it off the adjuster arm (manual only).
You should see three screws for fastening the mirror.
After he mirrors are replaced, pull out the white clips from the door and slide them back into the piece of trim then push it onto the door again. Or you can leave the clips in the door and try to slide the piece down over the heads of them.
Jmmy
August 2008