Sorry, very slow reply by me!
I had to write my own, and I unfortunately can't share the code with you, but I can give you some pointers.
You have to utilise the flex.messaging.FlexFactory which is setup in the services-config.xml of BlazeDS. In this I handled creation of beans and storage within ServletContext or HttpSession based on the scope defined in flex.messaging.FactoryInstance#getScope(). Be wary of beans stored in ServletContext as they are effectively available to any session and therefore any servicing web thread.
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