--- conversation.py	2012-12-13 03:32:12.123885675 +0100
+++ conversation.py	2012-12-13 03:32:39.287212515 +0100
@@ -358,9 +358,9 @@
     def _send_message_ex(self, content_type, body, headers={},
             callback=None, errback=None):
         message = msnp.Message(self._client.profile)
+        message.content_type = content_type
         for key, value in headers.iteritems():
             message.add_header(key, value)
-        message.content_type = content_type
         message.body = body
         return self._send_message(message, callback, errback)