I have a desire to finally change out the rear plastic bulhead window for the glass one I bought some 15 years ago. Finally. I am trying to figure out what the roof vent tube is attached to inside the inner plastic vent housing. It seems to me that the inner plastick housing is glued in place and drain hose go inside it...to attach to what? Is it just stubbed in there? I tugged a little to no avail. I just don't want to disassembly something I might not be able to reassemble. Will someone please enlighten me? Thanks!