So far I've only seen my creamsicle from Jimmy when I move the paper towel in his cage. Otherwise I have a lovely paper towel, water bowl & hide in view. lol Generally speaking, the snake will move around to where it is most comfortable. The only times my snakes bask for any length of time is if they're gravid (with my female boas) or ocassionally when they've just eaten (this more-so with my juvenile boas than the rest of the troupe).
As for the heat pad, do you know what temperature the pad itself is (versus the ambient air temps)? When I set up the melamine cage I built, I was told that the Ultratherm heat pads could be used without a thermostat. Well, as warm as I keep my house, the heat pad reached it's maximum...106F - luckily mine are wall mounted and not on the floor of the cage so the snakes weren't forced into direct contact. That temperature was much too warm for just about any snake to want to come into direct contact with. After I put all the heat mats on my Helix thermostat and set it to 92F (this is set up for boas and a juvenile burmese python, not corn snakes), the snakes were seen using the heat source off and on to thermoregulate...just as you would expect them to. I would check the temperature of your heat pad - a temp gun is preferable ( www.tempgun.com has the best quality for herpers' purposes, at an excellent price $25) but you can use a regular thermometer laid directly against the pad as well. The thermometer method isn't as exact as the digital temp guns, but it'll let you know generally how hot the pad is and if you need to turn it down.
Hope this helps!
Raven