WARNING: This page is about a different car, the 2008 Mitsubishi Lancer. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Rear Bumper Assembly Replacement Components With Torque Specifications (1 Of 2)
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Fig 2: Rear Bumper Assembly Replacement Components With Torque Specifications (2 Of 2)