'Excel has just created us... We take its callback for later, and set up shop.'

def ServerStart(self, CallbackObject):

    self.IsAlive = self.ALIVE
    if (CallbackObject is None):
        raise COMException(desc='Excel    did    not    provide    a    callback')
    IRTDUpdateEventKlass = win32com.client.CLSIDToClass.GetClass('{A43788C1-D91B-11D3-8F39-00C04F3651B8}')
    self.__callback = IRTDUpdateEventKlass(CallbackObject)
    self.OnServerStart()
    return self.IsAlive
