You save the prop that the hair develops from and the code to define the hair is a part of the library file. Poser 5 then redoes the hair from that code. The hair is not mesh saved as OBJ, it is code. There are scalp props that come with Poser 5 and since the hair can only be grown in Poser 5, there should be no objection to having the prop as part of a product. But doing your own scalp prop is not difficult either.