I am sorry, I didn't read your post well.
You were looking only for Earth Sculptor...

Someone made an exporter for Earth sculptor recently.
I will try to do a search for it....
I think I remember trying Earth Sculptor directly,
I think it has an export to heightmap (MED imports heightmap),
and also would have an image that would go with it.

If it had an .obj exporter, you can import it into MED that way too.


edit: yes, I checked it, it exports to .obj
but using the exported heightmaps and
multitexturing could be a little tricky.

-Jim