I haven't had much luck with the rooting hormone stuff (in general) either; somewhere I read that the shelf life of that stuff is microscopic - by the time you buy it, there's no life in it. I'm sure other folks have better luck with it.
Re: tomatoes, my spring seedlings seem to want to get up out of their pots sometimes; they develop the rootlings waaaayyy up their stems. You might try a couple things:
I have successfully layered a mature plant before - tip a branch down to the ground, scrape the branch a little where it will be under the soil, pile on some dirt, give it a few weeks et voila, cut the little guy offa the main plant.
You can try this with a less mature specimen by dropping some moist soil into a baggie and tying it around the tomato branch - esp. if the main plant is too young to tip over or have large enough branches to reach the ground. Bring the soil to it, as it were. The baggie should be cut open 'cause you're wrapping the soil around the plant, like a dirt bandage. A large enough plant could support more than one of these, I imagine.
Good luck!