Thank you very much Graeme. Pardon any ignorance here but actually I had already examined that page and looked at it again just now. I recall before (years ago) there was a separate download for the authoring-side communication components, which worked with Flash Professional 8 and Flash Media Server 2 (though they were AS1 components). The closest thing I see to that now on that page is the second to the last item:
Flash Communication Server Authoring Components Updater for Flash MX 2004
December 19, 2003
But that seems to be just an updater, as it says. But I actually did download it and try to install it but it said it found no Flash MX 2004 on my system.
Again I have Flash 8 Professional, and before I had the communication components (for Flash 8 Professional) that came from a separate download, and I just can't find that now. Maybe it doesn't exist anymore on the Adobe site (well it was actually Macromedia). Perhaps someone has it handy?