You'll probably have to take the lid off - look for a screw or screws under the main sticker by rubbing your thumb over it. The power option is likely to be a jumper rather than needing soldering, in which case it will be a very simple mod. Unfortunately, as you have found, there isn't much info about how to do this on the web.
Have a chat to Sam at Chainspeed - he knows his Autocoms and should be able to help you out.