I haven't been able to find any directions for that, although earlier in genvibe there were people who were swapping them out for billet grills and such, but nobody mentioned how to do it. I imagine if you took off the whole nose it would be fairly apparent, but that would be more involved (although not terribly complicated) than just reaching in there to do it.
Maybe a flashlight and a mirror will help you see in there to find the attachment points.
If you work on it without removing the nose, use a piece of cardboard as a shield or be extra careful to not ding up the AC and radiator fins
Thanks for the ideas on this. You were correct, the attachments for the grill and all the other trim and fog lights in the bumper cover are accessed from behind. No hardware involved, just clips molded into the bumper cover that you push to release. Here are links to photos from behind the bumper cover in case this of use to someone else.