Help! Broken Rear Speaker Grilles in 91 'Vert
 

I have a 91 convertible. When people rode in my back seat, they ripped the plastic rear speaker grilles right out. Anyone who has a convertible knows how much of a pain those grilles are, they are only held in by 2 black tabs, The black tabs are part of the body of the mustang, so has anyone figured out a way to fix the rear speaker grilles?? The grilles themselves are fine, its the part they are supposed to hook into that is broken.
Help please!