[SR-Users] Mid call announcement(kamailio server)

Hello, As of now am working on Kamailio server. My task is to announce in between call,my sip clients are EKIGA. I should able to make my kamailio server act as controller and media server,for that purpose my first step is : invite hold to called party. second step is:: invite(sdp for .wav file) to caller and then am sending rtp streaming.In wireshark am able to see rtp packets,but caller is not playing the .wav file which am streaming through ortp library from kamailio. Can anyone help me out with this problem?On top of it,is this possible in reality? Thanks & Regards, Manjusha A. Integra Micro Software Services (P) Ltd.