Lol I took out that same screw... It took me forever to figure it out, because I've never heard of anyone taking them off before. What you'll want to do it follow the shaft that attaches to the mirror, where it connects to the roof. Pop off that cover and there will be 3 screws there. Take them out and take the shaft off (that way you can see what you're doing when you re-attach the mirror and shaft.) Very carefully, with a razor blade, pop out the mirror surface from the casing. This is the only way to re-attach the screw, as there will be a loose plate inside the mirror that the screw threads into. Should be pretty self explanatory from there

Hope this helps...