I'm not a glass expert, but I thought tempered glass didn't like high heat. I could be wrong, but I would try some epoxy. Hopefully k [img]images/graemlins/grin.gif[/img]icking this back up will get some more ideas.
It should be current conducting epoxy. Does that exist? I once soldered a wire back to the shield. Clean it where you want to solder, tin the wire first, put some S-39 or so (no idea what stuf you use over there) and put the wire on when the solder on it is stil liquid. It should be right the first time. The chance you overheat the window is minimal. Succes!