A friend has an iPhone and can use it to send iMessages to a Samsung friend. She also has an iPad with cellular capability but it does not appear to be able to send messages to that person. Is this correct or are we missing something? I should think that it would be able to send imessages over the cellular connection if she, the iPad owner, is in contacts with her phone number but ...? If not correct, what would be a good app that can do this?