1. A method for chat-based communications between a legacy wireless mobile terminal and a non-legacy wireless mobile terminal, comprising: receiving an outbound chat message from the non-legacy mobile terminal, the outbound message including a legacy address corresponding to the legacy mobile terminal; detecting the legacy address; upon detecting the legacy address, building an inbound message that includes an originator address; injecting the inbound message into an out-of-band messaging system for delivery to the legacy mobile terminal; and receiving a reply message at the non-legacy mobile terminal, sent from the legacy mobile terminal in response to the inbound message.