diff -urB asterisk_orig//channels/chan_sip.c asterisk//channels/chan_sip.c
--- asterisk_orig//channels/chan_sip.c	2011-10-17 17:46:26.000000000 +0000
+++ asterisk//channels/chan_sip.c	2011-11-21 16:00:21.495571861 +0000
@@ -21124,6 +21125,8 @@
 	/* Mostly created to return proper answers on notifications on outbound REFER's */
 	int res = 0;
 	const char *event = get_header(req, "Event");
+	const char *subscription_state = get_header(req, "Subscription-State");
 	char *sep;
 
 	if( (sep = strchr(event, ';')) ) {	/* XXX bug here - overwriting string ? */
@@ -21242,37 +21245,58 @@
 		/* Confirm that we received this packet */
 		transmit_response(p, "200 OK", req);
 	} else if (!strcmp(event, "message-summary")) {
-		const char *mailbox = NULL;
-		char *c = ast_strdupa(get_body(req, "Voice-Message", ':'));
-
-		if (!p->mwi) {
-			struct sip_peer *peer = find_peer(NULL, &p->recv, TRUE, FINDPEERS, FALSE, p->socket.type);
-
-			if (peer) {
-				mailbox = ast_strdupa(peer->unsolicited_mailbox);
-				unref_peer(peer, "removing unsolicited mwi ref");
-			}
+		if(strstr(subscription_state, "terminated")) {
+			transmit_response(p, "200 OK", req);
 		} else {
-			mailbox = p->mwi->mailbox;
-		}
+		    const char *mailbox = NULL;
+		    char *c = ast_strdupa(get_body(req, "Voice-Message", ':'));
+   		    char *mw = ast_strdupa(get_body(req, "Messages-Waiting", ':'));
 
-		if (!ast_strlen_zero(mailbox) && !ast_strlen_zero(c)) {
-			char *old = strsep(&c, " ");
-			char *new = strsep(&old, "/");
-			struct ast_event *event;
 
-			if ((event = ast_event_new(AST_EVENT_MWI,
-						   AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mailbox,
-						   AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, "SIP_Remote",
-						   AST_EVENT_IE_NEWMSGS, AST_EVENT_IE_PLTYPE_UINT, atoi(new),
-						   AST_EVENT_IE_OLDMSGS, AST_EVENT_IE_PLTYPE_UINT, atoi(old),
-						   AST_EVENT_IE_END))) {
-				ast_event_queue_and_cache(event);
-			}
-			transmit_response(p, "200 OK", req);
-		} else {
-			transmit_response(p, "489 Bad event", req);
-			res = -1;
+
+		    if (!p->mwi) {
+			    struct sip_peer *peer = find_peer(NULL, &p->recv, TRUE, FINDPEERS, FALSE, p->socket.type);
+
+			    if (peer) {
+				    mailbox = ast_strdupa(peer->unsolicited_mailbox);
+				    unref_peer(peer, "removing unsolicited mwi ref");
+			    }
+		    } else {
+			    mailbox = p->mwi->mailbox;
+		    }
+
+		    if (!ast_strlen_zero(mailbox) && !ast_strlen_zero(c)) {
+			    char *old = strsep(&c, " ");
+			    char *new = strsep(&old, "/");
+			    struct ast_event *event;
+
+			    if ((event = ast_event_new(AST_EVENT_MWI,
+						       AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mailbox,
+						       AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, "SIP_Remote",
+						       AST_EVENT_IE_NEWMSGS, AST_EVENT_IE_PLTYPE_UINT, atoi(new),
+						       AST_EVENT_IE_OLDMSGS, AST_EVENT_IE_PLTYPE_UINT, atoi(old),
+						       AST_EVENT_IE_END))) {
+				    ast_event_queue_and_cache(event);
+			    }
+			    transmit_response(p, "200 OK", req);
+		    } else if (!ast_strlen_zero(mailbox) && !ast_strlen_zero(mw)) {
+  			    struct ast_event *event;
+                mw = ast_skip_blanks(mw);
+
+			    if ((event = ast_event_new(AST_EVENT_MWI,
+						       AST_EVENT_IE_MAILBOX, AST_EVENT_IE_PLTYPE_STR, mailbox,
+						       AST_EVENT_IE_CONTEXT, AST_EVENT_IE_PLTYPE_STR, "SIP_Remote",
+						       AST_EVENT_IE_NEWMSGS, AST_EVENT_IE_PLTYPE_UINT, strncmp(mw, "no", 2)?0:1,
+						       AST_EVENT_IE_OLDMSGS, AST_EVENT_IE_PLTYPE_UINT, 0,
+						       AST_EVENT_IE_END))) {
+				    ast_event_queue_and_cache(event);
+			    }
+			    transmit_response(p, "200 OK", req);                
+            } else {
+			    transmit_response(p, "489 Bad event", req);
+			    res = -1;
+		    }
 		}
 	} else if (!strcmp(event, "keep-alive")) {
 		 /* Used by Sipura/Linksys for NAT pinhole,