Normal Flipping in Grasshopper

Hi Folks,

I've been having some problems with a valid closed polysurface that has all surface normals oriented correctly in Rhino (used the Direction command). However, when I work with it in Grasshopper, it appears that half of the surfaces are now flipped (normals now pointing to the inside of the polysurface). I've tried to use a guide surface, I tried offsetting points along the normal to test for inclusion and then flip. I've even tried to flip normals manually by mutliplying the normal by -1.0...no matter what I try, can't seem to get all surfaces to be in the same orientation. Any insight would be appreciated...

Using:

Rhino SR6 on win xp
Grasshopper version 0.6.0019

Thanks!

~BB~

here's an image of what i get when i do the dir command in rhino:

here's what i see when i display normal vectors in grasshopper: