OK, here's a picture of the soldered on 4-40 nuts that I used in place of the supplied lock nuts. I didn't bother roughing up the brackets because they were so nice and shiny I didn't want to ruin the look. All I did was to remove the bracket from the plane, wipe it down with alcohol to remove any grease and then put some flux around the hole where the nut would be attached. Then, I took an alloy (black) 4-40 socket head screw (solder won't adhere to them) and a normal 4-40 nut and screwed them onto the bracket so the 4-40 nut was where the lock nut would normally go. Heat it up with your soldering iron and run a bead of solder around the nut. After its cooled down, remove the socket head bolt and reinstall the bracket on your plane. Simple

If your upper wing is already glued together (like mine was), you'll have to solder the nuts for the 4 upper cabane brackets with the brackets installed in the wing because there's no way to get them off wing. I did it and didn't have any problem. Just keep a damp rag handy and as soon as you take the soldering iron away, you can use the damp rag to wick the heat away from the bracket. Just don't hit the covering with the soldering iron.

If you're worried about your soldering skills, the worst thing that will happen is that the nut will fall off when you take the plane apart and you can re-solder it. Its not going to come off in flight. I have probably 8 flights so far and haven't had any problem with mine.