Steve,
There's a 3M, extra fine grit compound in a can (liquid, not paste) that might help you out a bit. Haven't tried it myself, yet, but, heard it's good stuff. It's about six bucks for the can. If it doesn't do the trick, you could still go to the detail shop. Ever since mine was at the body shop, my top (Black) has looked a little haggard (overspray from "something" I think), although they buffed out the rest of the car and it looks "killer." I plan on treating it this weekend. I'll let you know how it turns out, unless you want to play "guinnea pig" first.