Flash - Serialize Circular Object Networks Using Write / Read Object

I'm about to implement
public function writeExternal( output:IDataOutput ):void {...}
public function readExternal( input:IDataInput ):void {...}
to make a set of object serializable.

Although I'm pretty sure, that I implemented all correctly, readExternal(..) at a certain point complains about too few data left to read:
RangeError: Error #2006: The supplied index is out of bounds.
at flash.filesystem::FileStream/readObject()

I wonder, if I have a circular object network like
A = { left -> B, right -> B }
B = { father -> A }
And I call
writeObject( a )
Will Flex serialize the hole object network and each object once and only one?

I did this:
Declared type annotations like this: [RemoteClass(alias="model.MyClass")]
Implemented parameter-free constructors
Declared all classes using implements IExternalizable
SharedObject's send() method is guaranteed to send each object once and only once.

Additional infos:
Reading and writing a ByteArray
Using Remote Object Components
IExternalizable interface