A method is described for transmitting a multimedia stream from a first end-terminal to a second end-terminal. The first and second end-terminal are connected to at least one gateway for enabling the multimedia stream to be transmitted from the first end-terminal to the second end-terminal. The method comprising the steps of: the first end-terminal inviting the gateway to set up a first multimedia session between the first end-terminal and the gateway, the first multimedia session being controlled by a first protocol; the gateway notifying—in response to the invitation—the second end-terminal of the pending invitation; the second end-terminal setting up—in response to the notification—a second multimedia session between the second end-terminal and the gateway, the second multimedia session being controlled by a second protocol; the gateway setting up—in response to the invitation—the first multimedia session; and transmitting a multimedia stream from the first end-terminal to the second end-terminal. The first protocol may be SIP, the second protocol may be RTSP.