Welcome to Stratos!
Are you guys considering writing a stand-alone exporter for Haddd?That way you can probably add support for other mesh file formats as well.
Its just a plane with some noise added to it just to simulate some terrain.
I tried it again and checked the the contents of the exported file and chanegd the title PreHadddVersion13 to HadddVersion13.
Has the plane a material and texture coordinates applied?.
Haddd is strong on materials...
Maybe you should add some default parameters for the mesh if people don't set the material on them?