I have never done it in this car.But in the center there is a filler plate that pops out of mine every time I close the hatch.It has been like that since i bought the car, But I forgot to have them fix it during warranty.I would bet there might be something in there.Most panels are held on with those plastic push tabs anymore.
let say your sitting in the cargo area with the hatch closed.the are 3 tabs acrossed the topone in the middle and 2 about an inch in from each side.don't pry on the bottom of the panel there hooks down there. thats my trouble one of my hooks are broke.There is nothing in there holding the panel on thou, I just looked. but with that panel off you can easily reach in and push the tabs for the top panel that goes around the window latch assy but the window needs to be opened.