nut (I've used almonds) or a popped popcorn kernel (my preferred bait) into the bait bed claw. They can't just lick the bait off, they have to try to remove it.

EDIT: Ha, I just saw that you linked my post in your thread. Carry on! I hope it works! I had a mouse that I couldn't catch, it had babies, it went on for weeks. This is what finally worked for me. Make sure you put the traps in a high traffic area for the mouse. Good luck!