Also, to add to this, there are specific pieces of software [pt lens and nshift] that can correct barrel distortion, whether its the minor distortion you will get on, say for example, a kit 18-55 or 18-70, or the more obvious seen with 10-20/12-24 lenses. Both are available as free downloads, and pt lens is about £8 to buy full version. Both allow automatic correction and/or degrees of correction to your own taste.
I have HDR'd several shots from the 10-20 with no problems, but like others, I am wondering if you are perhaps confusing panoramics and HDR...perhaps you might want to post a link to a picture that demonstrates what you want to achieve.