handle in dialog requests for nat

kamailio/nat-traversal-role.cfg

@@ -75,6 +75,10 @@ route[NAT_MANAGE]
         setbflag(FLB_NATB);
    }
 
+   if ( is_request() && has_totag() ) {
+        setbflag(FLB_NATB);
+   }
+
    if (!(isflagset(FLT_NATS) || isbflagset(FLB_NATB))) {
         return;
    }