A method of Inter-User Equipment (UE) Transfer (IUT) for use in an Internet Protocol (IP) Multimedia Subsystem (IMS) capable wireless transmit/receive unit (WTRU), the method comprising: receiving a registration request from a non-IMS capable WTRU; translating the registration request to an IMS based message; transmitting the translated IMS based message to a Service Centralization and Continuity Application Server (SCC AS), transmitting an IUT transfer command, transmitting an IUT process message; receiving an IUT process-accept message; and establishing an IMS session between the non-IMS capable WTRU and the remote party.