I am gound flags for rtpproxy_manage(which help external (behind NAT) UA registerd on Kamailio call to Echo() test extension on Asterisk - it is "cwie". But for Peer-to-Peerm, registered on Kamailio and working though Asterisk dialplan, it must be rtpproxy_manage("cwii").
Thanks to author of this example of kamailio.cfg
https://github.com/xlab1/sipfe_kamailio/blob/master/kamailio.cfgAnd from Kamailio documentation for rtpproxy_offer([flags [, ip_address]]):
-
c - flags to change the session-level
SDP connection (c=) IP if media-description also includes
connection information.
-
w - flags that for the UA from which
message is received, support symmetric RTP must be forced.