Refitting awning rubber seal

[Fan the Van]

Having just removed the Thule (factory fit) awning on our Beach, to replace unglued original fabric, I have now replaced the cassette. The rubber seal between body/roof and cassette hasn't gone back so well at all and I wonder if there are different ways to locate the rubber. It now seems like there's a gap fore and aft with the curve of the roof. I didn't photograph the original fitting (d'oh!) Any suggestions? When I removed the cassette I seem to recall the rubber coming along with as I did so, but I may be mistaken.

 

[calikev]

The rubber seal has a t section that pushes into the awning rail

 

[Fan the Van]

The rubber seal has a t section that pushes into the awning rail

And then the wing points "up" and supposedly tucks into a channel on the back of the cassette?

 

[Fan the Van]

Pics attached

 

[Ocean Spirit]

I didn't even have a rubber seal from new.
Fat chance of proving that now I suppose on a 2017 vehicle. I guess its function is to stop rain dripping between the van and the awning especially when the sliding door may be open?