Yes, that is what I am using for the time being (registered version for higher resolutions but the method can be applied in the unregistered version as well) and I'd be glad to share the methods. Besides working on this project, I'm in the process of re-writing a rather poor tutorial I did on the process a short time ago. All in all, I'm using FTPro to generate the basic elevation files (with a grey-scale coloring scheme) then using FEO to import them into Terragen. Not having much luck with SOPack though, but am working on it.
As long as I don't have any major disasters at work, I should be posting the first few steps (and some detailed explanations regarding a few of the problems encountered) in the next two or three days over in the tutorials sections. I'm not an expert at it, but I am managing to hack my way through it.
GW