Sorry hon, but breeding an all black snake to an all white snake will not produce the black and white panda pied. It would be nice if it worked that way, but it doesn't.
A Super Black Pastel carries two black pastel genes, so no matter what you breed it to, all the babies will carry black pastel.
A BEL on the other hand, can be made from several different combinations, and the resulting babies will depend on which combo made the BEL. BEL's can be made from Super Lessers, Super Mojaves, Super Butters and a few other super forms, or it can be made by mix and matching two of these genes, such as Lesser/Mojave. A Super form BEL will produce babies that are all the same gene the parent has two of. A combo BEL can produce babies of both genes it carries.
A pied on the other hand is recessive. It takes two pied genes to make a visual pied. So to make the elusive Panda Pied, you need two black pastels, both of whom are either het pied or visually pied, or one het and one visual. Each parent would need to contribute one black pastel gene and one pied gene, and then you hope like crazy the genes combine the right way and you get a visual super black pastel pied. However, even in the best case scenario, by breeding two visual black pastel pieds you still only have a 1 in 4 chance at hitting the panda pied. And if you are breeding with hets, it gets even harder. That is why there haven't been many panda's made yet.
Gale