Rear Seat Removal

I just bought a 1991 5.0 LX ragtop--the top goes up and down fine, but the right rear window won't move. The motor spins but the window won't budge--I presume it has plastic parts in the regulator that need to be replaced. I'm familiar with this from other failed regulators in other Fords. My problem is removing the rear seat. The bottom cushion is fastened so solid I can't get it to move at all. Maybe there is a special technique to remove it?? I tried the same method of removing all rear seats--push hard on the front lower edge of the seat and they usually come up and out--but this one doesn't move AT ALL.
I presume with the rear seat removed it will be obvious how to remove the right side panel around the rear window mechanism. I should be able to handle it from there--but I'm needing to remove that seat, aren't I?
I tried the search button and got nothing.

I got my rear seat out by accident--I was following the above suggestions and luckily got it loose. It turns out my seat comes out fairly easily, I was being too gentle. I made a nice wedge out of a piece of junk 2x4 and used it to raise the seat cushion by driving it between the floor and lower seat frame. When it was elevated a bit I hit it along the front edge as I suspected and it "sprung" up fairly easily. As with all things with Mustangs it was fairly easy once you know how. With the '91 convertible the braces that hold the seat down are made of "U" shaped pipes about 1" in diameter. The cushion has hooks molded right into the seat base. When its in place it is VERY secure, but luckily my homemade wedge was exactly the right thing to encourage the seat to let go.
The seat-back cushion just lifted off the rear bulkhead and then I could remove the screws to remove the side panels with the speakers in them. I am re-installing both panels because the last guy who took them off did a very poor job of installation, nothing was fastened correctly.
The original problem of the dead power window regulator was easily fixed by removing the bad ground up plastic inside the gear housing and I replaced the three 'rods' with some I made out of nylon/plastic--very resilllient. The motor was fine, so with the new plastic parts it works like new again. Easy fix!
Now for a more careful reassembly and my back seat/panel/window regulator will be as good as new. Its satisfying to fix/repair simple things and get a nice result without spending any cash.