[Freeswitch-users] switch_r_sdp change for 183 and 200 OK

I am trying to experiment few things that required me to change SDP (Using media bypass mode). I am able to change switch_r_sdp from a /perl/lua script successfully for Invite message using ... $session->execute("set","switch_r_sdp=$$resp{sdp}"); but I also want to change SDP of 183 session progress message I tried executing same code in scripts fired on 183 message but it doesnt seem to be changing SDP Is that even possible? John