Heck I just pulled the fairing, used my little hand held laser pointer (key chain style) put it on a table across the room and aimed it at the bolt with the fairing off... ran over, hung the fairing on the bike and looky!! a red dot at the hole centerHeres a lil trick I learned from the techs at my shop.
1. Remove fairings.
2. Find a bolt that fits in the frame where your slider would be bolted to.
3. Grind off the head of the bolt to a point.
4. Screw the bolt with the pointy head into the frame, then reattach your fairing.
5. Gently push your fairing into the bolt so that it will leave a mark on the inside of the fairing.
6. Remove fairing and use that mark as the center point when drilling your hole. Start with a small hole cutter and use the dremel if needed.
Its kind of a timely process, but well worth it cause they always line up perfect. Clear as mud?

Guess I could have taken pictures but it went pretty darn fast..