Index: main/rtp.c
===================================================================
--- main/rtp.c	(revision 53494)
+++ main/rtp.c	(working copy)
@@ -2211,6 +2211,9 @@
 
 	rtp->dtmfmute = ast_tvadd(ast_tvnow(), ast_tv(0, 500000));
 
+	if (!rtp->send_payload)
+		rtp->send_payload = ast_rtp_lookup_code(rtp, 0, AST_RTP_DTMF);
+
 	rtpheader = (unsigned int *)data;
 	rtpheader[0] = htonl((2 << 30) | (1 << 23) | (rtp->send_payload << 16) | (rtp->seqno));
 	rtpheader[1] = htonl(rtp->lastdigitts);