Couldn't you simply use an exacto knife or razor to seperate the barrel battery from it's support brackets, and then just solder the wire to the brackets themselves? Thus not soldering anything to the motherboard itself and reducing the risk factor a great deal?
I would also highly recommend covering the rest of the motherboard up with news print as you'd really hate to accidently splatter solder onto the motherboard. I accidently did that but luckily the solder didn't land anywhere important. *phew* :-o
- Mike
