// Get the "my-role" mex from the DB.
MessageExchangeDAO myrolemex = _dao.getConnection().getMessageExchange(mexId);
Operation operation = plink.getModel().getMyRoleOperation(opName);
if (operation == null || operation.getOutput() == null) throw new NoSuchOperationException();
// TODO what if msg==null? i.e. for a reply-with-fault.
MessageDAO message = myrolemex.createMessage(operation.getOutput().getMessage().getQName());
buildOutgoingMessage(message, msg);