You are modeling for GDK? (Edit: Yes you are, i should read more carefully
)
Convert this functions from DBPro:
"Set Object Transparency ObjectID, 4"
I suspect the DX viewer wont apply transparency so the foliage will be opaque.
Edit2:
If that is your problem, or is it not texturing at all?
The materials often borks up the textures and its easy to apply the texture wrong in the UV editor.
In that case, In Blender, remove all the materials if you have applied any. Then in the UV editor delete the texture image. In Edit mode select All vertexes and reapply the texture image in the UV Editor.
If you use normalmaps apply the shading manually with code in DarkGDK.
Regards