Ok, after reading this thread as well as the other, titled "Sunroof Fun," I was confident enough to try this on my own. It went flawlessly, and I remembered to grab my camera before I put it all back together. Hopefully this will help you all in your quest!
Pop up the sunroot into tilt, and then slide back the cover. First you need to take off the accordian-like covers. If you look in through the outside, you can see they are snug against a post on the frame of the sunroof mechanisim. Either start there, or inside by pinching and pulling. It comes out easy. Then remove the sunroof glass by taking out the 6 "Torx 20" screws. Once that's out, you'll have a great view of what's going on.
On the sunroof rails, there are these silver trays that hold the clip mechanisim that holds down the posts of the rear windscreen.
Tray on rails:
Clip that should be in the tray:
Post on back of windscreen:
Luckily, my clip only had popped off the tray. A previous poster (I think in the "Sunroof Fun" thread) actually had his rolling around in the headliner and had to fish it out. My clip was still attached to the post, but not to the tray. I then popped it off the post, and had it seperate. There are 3 holes in the tray, and three little nubs on the clip. It's pretty easy to see how they go together:
I put a little Gorilla Glue (just a smidge, as it expands...feel free to use epoxy, JB Weld, whatever) on there to motiviate it to stay put. I didn't opt for a more powerful glue, as nothing had broken, so didn't want to seal the deal. Put the clip back on the tray,
and then work the tray so it is directly under the windscreen post.
Press down and the post will 'click' very solidly back into the clip/tray assembly. If the clip itself is broken you may have to improvise.
Reassembly is super easy. Put the glass back on, and put all the screws back in loosely.
Then close the sunroof. It will be too low. Go outside your car and reach in with one hand and lift the back until it's just *barely* under the roofline. Tighten the back. Do the same then to the front. Then do it all over again on the other side.
The accordian covers are pretty easy. The bottom just slides into the track, and the top into the two pop holes, and the back on that little post.