[Freeswitch-dev] I can not see sendonly/recvonly from SDP

hey I am using mod_esf to do the multicasting. In bypass_media mode, it will send recvonly SDP to other side. I use wireshark to catch the sip/sdp packets, but I can not see freeswitch sent recvonly inside SDP. After that, I try to set NDLB-sendrecv-in-session to be true (specified here: http://wiki.freeswitch.org/wiki/Sofia_Configuration_Files#NDLB-sendrecv-in-s... ). It still does not send recvonly to the other side. Did I miss anything? I also want to allow softphone to be multicasting listener, is there any extension module to do it?? Cheers Xijing Dai