I am replacing the MB-tex bottom seat cover on my 1998 C230.

Had no trouble rebuilding the cushion with the new MB-tex cover.

My problem is getting the stiff card-board surround on the new seat cover to fit under the metal lip of the seat at two particular points.

On the side of the bottom seat frame near the front, right above where there is an attachment for an articulating arm, I cannot get the new MB-tex' covers bottom border to push up into the lip.

Anyone familiar with what I'm describing?
Any tips?