I cut the flap off of my OEM case. It just makes it easier to retrieve and put back. I also ordered the Seidio skin for it and have no doubts that it will fit into the OEM case.
~via BB (wap.pinstack.com)~
...Now have the rubberized black Seidio thin skin and my BB fits more snug in the OEM case with no flap. Perfect for me.