look at the inside of your buttress..inside the car, you will see a metal cable attached to a linkage that hold the rubber seal against the window, that is the cable that releases the buttress, it should be very thight/flexed, if not it has come off its track and needs to be reposhioned in that track.
by pulling the cable from inside to make it tight, try releasing the trunk with the remote, the buttress should pop out now.be sure your trunk is closed first.
you can see the cable in this pics, look at outside part of the buttress, the cable should be tucked away in a chanel, that is what keeps it tight and spring loaded and pulls on the buttress.
http://putfile.com/pic.php?pic=9/25313533546.jpg&s=x4
i have seen a picture before on this forum...look for it.