Anyone know how to remove the blackplastic threshold trim under the tailgate?

[bcolins]

I want to remove the right rear storage bin that is in the very back corner of the rear storage area, across from the tool kit. It is captured by other bits of trim around it,...and I am trying to remove or loosen them, so that I can get the bin out to clean it.

I have all the fasteners (6) holding the rear threshold black trim out,....and I still am unable to remove it,.....it is captured by the vertical side trim pieces where they connect.

Any suggestions on how to release the trim bits?