Surface Shader problem
 

I have a BIG question on Surface Shader hoping someone can help me out.
Everytime when I apply a Surface Shader on a non-primitive Poly geometry, the areas didn't covered by the UVs become black in the UV Texture Editor. It make texturing like hell and sometime cause problem in rendering. :(
Any suggestion? Thanks.

http://server5.uploadit.org/files/sevenof9-helpme.jpg