OK, so this might not really be the answer you're looking for. Assistance/service dogs aren't a trait that can be bred. All the breeders that claim to breed service dogs are BYB. NOW, that being said, certain breeds are better at service work than others. Since you want to breed your dog, it does make things a LOT more complicated. First of all, you need to make sure your dogs breeder is ethical. I don't exactly know the reason you want that particular cross, so I say just breed her to her breed. The most important thing before breeding her though is, that she's proven in something. As I said, assistance work is not something that can be bred for, so you'll need to at least prove her in the show ring, or in a dog sport such as agility, etc... or a mix of those. Then, you'd need to do EXTENSIVE health screenings, more specifically the ones your breed club requires. If you dont have a mentor/breeder, I wouldn't do the breeding, breeding dogs is hard, and without the right mentor you could easily lose track