Been having a strange issue with iMessage ever since launch. When I start a new text conversation with one of my contacts that I've messaged by iMessage before, the initial message is sent via SMS and not iMessage. His reply comes via iMessage and from then everything is fine. But if I delete the conversation and start a new one later on it goes by SMS to start with again. He says his phone is set to receive at both his number and email and mine is too. Is this normal? I thought it was supposed to remember permanently and not per conversation.