I can't help you with a rememdy but I can tell you that I have the exact same problem. I sprayed dimension in the fall and surflan in the spring. It seems as though the mild winter here (OK) allowed the henbit to germinate directly between my standard spray pattern. Thankfully, it's the first weed to go when you take a low mower blade to it. It doesn't change the fact that my yard looked terrible this past month. I'm going to up my dimension application rate (still within the label guidelines!) this fall to see if it'll provide longer coverage. Of course, if you're willing, a good dousing of glyphosate on the dormant bermuda wouldn't hurt...but, I'm kind of opposed to that when a little heat and a few cuts will clear it up in my yard.

One more tidbit: weedalert.com states that henbit germinates (on average) in December in your area and November in my area. Of course, that's subject to soil temps and other factors. I'll have to go check my notes but I thought I had preEm down in early Nov.

If you don't have much henbit, it is just about the weakest plant on Earth. You can pull it out very easily.

Lovethempokes wrote:
....henbit germinates (on average) in December in your area and November in my area

You're lucky. Last year, henbit started sprouting in September in my backyard.

And lots of little new ones have been sprouting this month, especially in grass-seeded bare spots that I've been watering. Wow, henbit loves water.