Use rtpproxy_offer()/rtpproxy_answer().

modules_s/nathelper/nathelper_rtpp.cfg

@@ -48,7 +48,7 @@ route{
 	if (method=="INVITE") {
 		record_route();
 		if (isflagset(1)) { # ATA ?
-			force_rtp_proxy();
+			rtpproxy_offer();
 		};
 		/* set up reply processing */
 		t_on_reply("1");
@@ -69,5 +69,5 @@ route{
 onreply_route[1] {
 	if (status=~"2[0-9][0-9]" && search("Server: Cisco ATA.*"))
 		fix_nated_contact();
-		force_rtp_proxy();
+	rtpproxy_answer();
 }