The way the back seat is held down is quite shocking. In most cars you have a tab you can pull on to release it, but unfortunately on the Aurion it is just a matter of pulling the seat up with some force. There are two 'clips' that hold the seat down and it is best to squeeze your hand as close to the clip as possible and pull up. If you have larger hands, you can use a long screwdriver to lever it up. It's kind of hard to explain; but if you use a torch and look under the front end of the seat while trying to raise it, you will see what I mean.
Once that is out, you can remove the back rest portion of the seat by removing three bolts that are located near the bottom of the seat belts.
In addition, there are step-by-step instructions in the appropriate service manual:
http://www.camrystuff.com/manuals/Gen6/2GR-FE/Seat.pdf (page 47)
Hi sorry for bothering but am wondering if you can get in behind the top part of the back seat in an 09 aurion? I have to put the seat covers on and have no idea how to even attempt the back seats.