How do you reattach the silencer switch to the new power flex?

During the time I did repairs, I never did melt them down. Once it is seated in the metal part I would just hold it in place until you could get it back onto the phone and once you put the screws in it holds it in place no problem. If it is still loose though, Just fold a piece of paper and wedge it between the battery and the rocker switch and will have nowhere to go.

don't do that. heat your tweezers with a bic lighter and melt it with that, heat a nail and melt it with that. screwdriver, really pick your poison. Do it right, you'll appreciate it down the road.