A method and mechanism to allow a location server to initiate a user plane location service (e.g., SUPL defined by OMA) procedure to a user plane enabled device via Instant Messaging, or alternatively, via an existing SIP session if a multimedia session is already established. The location request is signaled to the user plane enabled device via a SIP INFO message. The location request uses SIP messaging to overcome firewall and other network security issues. Location using SUPL over SIP may be provided about a caller making an E911 emergency call. An Instant Message may be sent to the user plane enabled device, e.g., a VoIP wireless phone.