the JMX method dumpStats() on a MuxChannel displays information from the "super" channel.
So, I suggest:

• making the private method JChannel.dumpChannelStats() protected
• replace the content of MuxChannel.dumpStats() with:
  Map retval=mux.getChannel().getProtocolStack().dumpStats();
  if(retval != null) { Map tmp=dumpChannelStats(); if(tmp != null) retval.put("channel", tmp); }

  return retval;

After this changes, the JMX method dumpStats() will display the protocol for
the current MuxChannel and the correct number of sent messages.