bmrt export

Hi
I’m new to this forum and i have two little questions !

I’m trying to export a character with blenderman to bmrt but I’ve some problems :

The scene has 25 meshs, bmrt renders all but not the head. I duplicated it, flip normals…; and re-export, the problem is still here. I don’t know why !
Some ideas ?

My second question is about materials: I want my character in one mesh. So after the modeling and texturing, I do “CRTL+J” on my meshes to have one. In Blender the chracter keep all the material. How can I do in Blenderman to put 4 or 5 mat to my character ?

Thanks
Fuzz