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.