Can I watch PPV boxing undercards on Yahoo Sports?

I know if you order a UFC PPV event on Yahoo Sports, you are able to watch the untelevised undercards. Can the same be done to an HBO PPV boxing event? Could I purchase an event like Pacquiao-Cotto online through Yahoo Sports so that I can watch it legally and view all of the untelevised undercards as they happen or will it just be the three undercards that will already be televised?