Rear Window Exterior Trip Messed Up

[squeasel]

If there were a topic "How did you screw up your X5 today?" I would have posted there.

I replaced the left rear window regulator on the 2003 X5 3.0. I cannot get the exterior trim piece on properly, where it fits towards the front. The first photo shows that it does not "Lock" under the window frame (note that the length is OK sort of an optical illusion in the photo).

The second photo shows the underside of the strip. There is a small "tear" perhaps OK because this is where the strip has to jump a ridge to get to the in front of the window. Also there is a small "tab" built into the strip. It might be broken. To me this tab seems like it should fit into the window frame.

Did I break something? And do I need to get a replacement part? Or do I not know the proper technique for re-installation? Or something else?

All help appreciated.