The latch release sounds like it failed internally. Perhaps the link arm has broken and now feels sloppy? You need to find a way to manually trip it which may be near lock-smith skill to fish around blind?
With the other "test" seat down try tripping the latch on it manually and examine how it works. If there is a way to lift the latch (from behind), maybe with a slim metal ruler or coat hanger, you could slip it behind your stuck seat and pop her - once. That sounds slightly tricky. There may be a way to slide a tool down through the outside release and jimmy it? Lastly, you could look for latch mount point screws from inside the trunk. Removing a couple screws may allow her to drop and you can get to the broken release.
I don't have folding seats just thinking of ways to cheat that dratted dealer. Have you tried pulling back on the seat while operating the release? Also whacking the release area with Bruce Lee palm shots may do some magic from impact. That one is a little strange but cams and springs can often get hung where a whacking releases 'em.
Anything made can be made Better
Last edited by White_Knuckles; 11-03-2012 at 12:39 PM.