[Flow] __clone method isn't called

[Alexander Wende]

Sorry, for posting so much flow questions. I promise that I tried to find a solution on my own first. But there only a few  flow ressources in the net. The documentation helps a lot, but not in any case.

When I clone a model object, the __clone methos isn't called.
I noticed that the in  the file in the cached Flow_Object_Classes contains an own __clone method which is called when I clone the object.
In the cached __clone method there is an flag $this->Flow_Aop_Proxy_methodIsInAdviceMode['__clone']. If set, the parent __clone method will called.
But how I have to set this Flag? Or is there a better way to call the __clone method?

Thanks in advance