This question is slightly off topic as it is about a predecessor technology, but if anybody knows an anwser they must be present here.
We're currently working on a Flex / swf panel launched via CS4 InDesign's extensions mechanism, in a similar way to the Kuler extension.
As I understand it, in this specific environment the flash player is not instantiated via ScriptUI, but rather by a native / plugin window.
Is there a way to address that flash player from within ExtendScript, e.g. the equivalent to ScriptUI's invokePlayerFunction?
Why don't you address it in C++ and create a scripting call so you can use the C++ call as a bridge?
that's my fallback approach. The client prefers scripts over plugins because they can maintain those themselves.