Member hart24601 has a BB tank with plants glued to rocks and wood. You may be able to search the thread he started with great pics. I msg'd him for details. He uses super glue gel. Apparently only the gel works and you can even glue underwater. Apply to the plants rhizome, let a skin form, and then apply to the wood or rock as desired. The roots will eventually take hold themselves.
I have not tried it as yet, but i did buy the glue. Just not sure atm if I'm gonna add plants.
Let us know how you go!