Sabino Registry? What else can I register her in?

My pony is unregistered. I can register her had a sabino, but I would like to get her registered somewhere else as well. I know who her dam is (I'm not sure that she is registered either.), but not her sire. Her owner before the rescue I got her from left his stallions in a field with all the mares (What a bright idea. NOT!) so who knows which stallion bred the mare. So basicly I don't know her pedigree (at least on the sire's side) so I can't register her with the Welsh Pony Registration. Any ideas would be greatly appreciated! :)