Hi Edgar, can't add anything 100% to what your exact issue is however, maybe you could try the Blender route... for which the exporters are well known working. I'm sure you can convert/import your model into Blender with ease, least you will know for sure your export should be as you see it in Viewport.
Regards Cecil -- http://groups.google.com/group/realxtend http://www.realxtend.org