WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
Open the lift gate.
Open the rear compartment storage lid.
Remove the seat anchor nuts from the rear storage compartment.
Remove the rear storage compartment.
Fig 1: Removing Procedure Of Storage Compartment - Rear (Rendezvous)