Anupaum, I don't want to derail the OP, however, I did run my own VSS on a WM V4 and it does still work.  Weight mapping has not affect it.  But I did find that if the original skin texture nodes are named something other than image_map, then the nodes become disconnected when VSS is synchronized.  I went back into the Mat Room, copied the offending nodes (in my case, the skin texture I was using had Color_map instead of Image_map) and pasted them back.  That will rename them to Image_map.  Reconnect them to the PoserSurface and synchronize again.

But I would double check the original skin texture first.