I have it broken now too. It can be replaced by desoldering and soldering a new one. They are cheap on eBay. If you can't fix it yourself take it to a phone/computer shop.
My phone autostarts when connecting the USB port because i am using devil kernel, and i have slim bean ROM, with hardware keys enabled and the function to turn off the screen assigned to long press menu button. I can also turn off the phone using this ROM via another touch controls in the drawer (long press over turn off touch button). So i don't have to take the back cover off.
P.S: i supposed that you were talking about the screwed internal back cover. If not, and the problem is with your plastic material then another solution should be possible.
Enviado desde mi GT-I9000 mediante Tapatalk