--- res_rtp_asterisk.c	2012-06-21 13:41:34.780470962 +0200
+++ res_rtp_asterisk.c	2012-06-21 20:54:15.530623741 +0200
@@ -802,6 +802,8 @@
 				    ast_sockaddr_stringify(&remote_address),
 				    rtp->send_payload, rtp->seqno, rtp->lastdigitts, res - hdrlen);
 		}
+		rtp->seqno++;
+		rtpheader[0] = htonl((2 << 30) | (rtp->send_payload << 16) | (rtp->seqno));
 	}
 
 	/* Oh and we can't forget to turn off the stuff that says we are sending DTMF */