re-attaching cladding

[thatchman1]

The wheel well/cladding (whatever it might be officially called...) has come unattached.

I've done the normal try to pop it on, get at it from below, etc. It looks like I need to remove the outer beveled part to push this expansion plastic snap back in.

However, its held on with something that is not hex, phillips or flat head. Anyone know what this of attachment screw takes?

Surely this thing isn't a one use and replace item as far as this strange screw hole goes.........

Any recommendations appreciated.

The cladding popping off:


In the right rear wheel well where it appears I could get in there if I knew what to remove these with: