On November 12, 2006 I posted an article on this blog addressing some serious issues between Flash 8 (MX) and Quicktime. >>read it here<< On April 15, 2007 Adobe finally issued this tech report: "QuickTime does not support Flash Tracks beyond Flash version 5. You can, however, export a QuickTime movie with Flash rendered as video by selecting File > Export > Export Movie".
You can read the full Adobe tech report here:
How interesting! :)