The soldering iron was excellent advice! I just performed this delicate surgery myself and used an Exacto knife to slice the top of the old plastic posts off that hold the sensor disk in place. Then it was just a matter of prying the sensor disk off (although that middle square was stuck on there pretty good). I smashed the sensor disk down on the new backplate after aligning the posts and melted down the posts slightly with a soldering iron and the sensor disk is staying in place great. The magnet or vibrator motor or whatever that is at the bottom took quite a bit of effort to remove and transfer (I'm guessing it's the vibration motor as there are two tiny electrical connection arms at the sides, and after I removed it the old backplate would still stick to the charger). Eventually I cut enough of the old glue and pried back enough of the surrounding plastic rectangle that I was able to finally pry it up. I then used a little hot glue to secure it to the new backplate. I am extremely happy to report that...