well i did it once before, im in the process of glassin them right now
1. take off the whole door panel
2. get your dremel and grind off the plastic rivets
3. remove old fabric
4. clean off all glue and remainder of fabric
5. adhere new fabric
6. use some plastic epoxy to hold the insert in place
7. make sure its dry
8. reinstall door panel.

sounds easier then it is, take your time and have plenty of extra fabric...