Sunroof Leak - not the drain lines this time

[DaughtersSC2]

After reading about clogged drain lines causing sunroof leaks - decided to remove headliner. Found both rear drain lines disconnected from Sunroof - thought - cool - easy fix. Blew them out - and reconnected. Unfortunately - still have a leak (although Im certain reconnecting them has probably helped somewhat).

In any case- there was a piece that seems to be disconnected. Found it "under" the roof -but above the sunroof (in the slot that's at the rear of the sunroof when first "opened"). Looks like a "channel" of some sort - even has velcro on the bottom (where I'm assuming the headliner connected). It has missing rivets (one at each end). Looked like one was ground down - so assuming previous owner had something to do with this.

Seems like this piece missing is whats causing the problem - but cant tell exactly where it goes. Seems like it should be the rear "dam" for the water. Some of the water runs into where the drain tube connects - but some goes past that. Anyone had experience with this -or knows how it goes and a way to fix it?