I just did it as shown in video. The hardest part for me was twisting the mirror back on. The great news is IT WORKED! Mine had no discoloring or dirt but I wiped the antenna and parts with an alcohol wipe (for lenses). Very happy and thankful for this video.
I will be trying this asap on my 2011 E93. After watching this video I put my fob against the windshield on the rear view mirror area and touched the door handle. It locked and unlocked with each touch. I have a feeling following this video will solve my problem.