The other day I ran into a similar problem with a cab for my friend. What we did was took a piece of clear packing tape, cut it to about 2 inches long, looped it over itself so the sticky part was outside, laid it across the slot, then pushed the t-molding in. We did this every two feet and next to curves/corners. Worked great. The tape isn't visible, and the t-molding is holding well in place.