diff --git a/channel.go b/channel.go
index 4975f1b..12e7dc8 100644
--- a/channel.go
+++ b/channel.go
@@ -104,7 +104,7 @@ func (ch *channel) sendEvent(e *Event) error {
 	}
 
 	if ch.Id != "" {
-		e.Header["response_to"] = ch.Id
+		e.Header["response_to"] = []byte(ch.Id)
 	} else {
 		ch.Id = e.Header["message_id"].(string)
 
diff --git a/event.go b/event.go
index 8edae65..2f3de3a 100644
--- a/event.go
+++ b/event.go
@@ -49,7 +49,7 @@ func (e *Event) packBytes() ([]byte, error) {
 
 	var buf []byte
 
-	enc := codec.NewEncoderBytes(&buf, &codec.MsgpackHandle{})
+	enc := codec.NewEncoderBytes(&buf, &codec.MsgpackHandle{WriteExt:true})
 	if err := enc.Encode(data); err != nil {
 		return nil, err
 	}