Question on adding vegetation to terrain.

Hi!
First real post I have made here looking for some insights. I have created some terrain using Terraland. It creates terrific real world terrain! I also have World Creator Professional, Terrain Composer and World Composer.
What I am trying to do... is find a tool that will allow me to add all that great vegetation that those procedural tools provide... to my existing terrain made in Terraland.
It is important I use real world terrain in the most detail I can find... and would like to know if I can get any procedural terrain tool to recoginize the existing terrain and add that to the project before I add the vegetation.

Can any of you opine or have recommendations on what I can do?

Thanks for your time.