'Create a new message in the queue.
@rtype: 2-L{tuple} of (0) L{file}, (1) L{FileMessage}
@return: The envelope file and a message receiver for a new message in
the queue.'

def createNewMessage(self):

    fname = ('%s_%s_%s_%s' % (os.getpid(), time.time(), self.n, id(self)))
    self.n = (self.n + 1)
    headerFile = open(os.path.join(self.directory, (fname + '-H')), 'wb')
    tempFilename = os.path.join(self.directory, (fname + '-C'))
    finalFilename = os.path.join(self.directory, (fname + '-D'))
    messageFile = open(tempFilename, 'wb')
    from twisted.mail.mail import FileMessage
    return (headerFile, FileMessage(messageFile, tempFilename, finalFilename))
