Steven Andrews:

That is an easy fix and I used something to modify an ET pouch for a cell phone thusly:

Glue some heavy weight foam to the underside of the flap so that it is pushing on the knife when the flap is closed.

If the knife sits too low in the pouch, drop in a piece of wood in the bottom of the pouch to hold the knife higher.

If the pouch is too wide either front to back, or side to side, make a "U" shaped filler to put in the pouch to take up side to side motion and bring the knife up a little higher in the pouch.

For controlling front to back excess, glue a wood spacer to the inside back of the pouch.

Good luck!

Bountyhunter