--- channels/chan_sip.c	2010-09-01 18:16:28.000000000 +0200
+++ channels/chan_sip.c	2010-09-01 18:17:03.000000000 +0200
@@ -10021,7 +10021,7 @@ static int add_rpid(struct sip_request *
 	const char *fromdomain;
 	const char *privacy = NULL;
 	const char *screen = NULL;
-	const char *anonymous_string = "\"Anonymous\" <anonymous@anonymous.invalid>";
+	const char *anonymous_string = "\"Anonymous\" <sip:anonymous@anonymous.invalid>";
 
 	if (!ast_test_flag(&p->flags[0], SIP_SENDRPID)) {
 		return 0;