I had a couple that took a little coaxing to get out, but I've never had to heat them. But what I'd suggested (over-analyzation of the situation and all):
... if you're having trouble, perhaps your pin is too short? Some of mine needed more pressure than others to pop out and it's kind of hard to do that when the push pin you're using is already completely flushed against the bottom of the casing with the bottom of the push pin (did that make sense?).
... also, I think the pans are kind thin, so it your problem the fact that the tip is just pushing through and therefore not being able to push against the glue? In ths case, try a pin with a slightly larger diameter (but if there's already a hole here, that might just enlarge it even more without popping out the pan).
... if you're pushing with the lid closed, try opening it a bit to allow the pan to go somewhere. Otherwise, you're just pushing it against the lid and it won't "pop" out; it'll just shift slightly but still be held in place by the glue.
... I agree with the above. Try to heat it lightly to loosen the glue (a few of mine were stuck in there surprisingly tight) and try again.