A lot of times you can GENTLY pry the UTH up just enough to shove the probe underneath it. Otherwise, you can try this: http://ball-pythons.net/forums/showt...removing%20UTH

I only attach a UTH to a tank/tub using aluminum foil tape, not the built-in sticky stuff, so that it can be removed, transferred, etc., as needed (I know it's a bit late on that to help you).