I read your first post on this when you first posted it. I'm surprised you haven't gotten that little guy out yet.
There's no real way to coax that snake out. You just have to wait until it's out, and grab it. All these people saying 'bump it out with ur subz! turn teh heatz on! lololz!' ... that'll just keep the snake comfortable or scared. Either way, that wont make it come out. He'll either be too scared to move, or too warm and comfortable to move.
Your best bet would be to try and come up with a snake trap or something. It'll take some effort, and I don't know if a snake is smart enough to get out of it... You'd want a little hole that the snake could barely fit through, and make it a funnel shape going into the box. So it's easy to get into the box, but hard to get out. Much like a fish trap. Snakes have a VERY keen sense of smell, and if he's hungry.. he'll come out within an hour of smelling that mouse. I guess you could keep an eye on the trap, and wait for the snake to show himself if you had the patience.
Trust me, I have a beautiful hypo boa. She's usually fully aware if I walk into the room with her food, 10 feet away.
Good luck.