Body/Trim: rust under rear window

[laszlo]

As if a decomposing tailgate would not be bad enough, a nasty rust spot has started to develop under the left side rear window, estate cargo area (see pic). More alarming is that spot gets wet when raining thus it seems window is leaking water either between rubber trim and glass or rubber trim and body. Volvo green book suggests to remove window, drill out rivet, seal hole (rivet hole? – dunno) with body sealant and install new sealing list part nr.: 1372174. Could somebody please comment on this job, do I really need a new sealing list from Volvo or is it possible to find a suitable alternative/another solution. I gather from previous posts that removal of the rear window is by pushing the rubber trim over the metal lip from the inside, working slowly around. Never done that before and I’m a bit scared what I’ll find under that rubber trim…..
Thanks for your input,
Regards,

Laszlo