normal bump rendering using global illumination

I think I figured out the problem here.  What I typically do is add only a 
skylight in the scene and use light tracer to do a GI render pass.  It 
usually gave me good enough result so I figure it'll work for an object with 
normal bump applied to it.  BUT it turns out that with only skylight in the 
scene, it sort of blows off the normal bump info.  So the fix is really to 
just add other lights into the scene and everything's fine (although this 
require a little more work to get that GI look back).  Go figure... :-)