same problem here. do you found a solution?
This question comes up occasionally on the forums. The short answer is not in Catalyst. The long answer is you might be able to with a lot of tweaking in Builder, but it is not supported. Please read this post by Peter Flynn for a more complete discussion.
There must be a way to do so.. What if you don't use any of the new features FLEX 4 introduces, like 3D rotation? (I'm not sure this has anything to do with FLEX 4, just trying to make a point here..)
Save the files, and open it with older software that only supports flash 8 / 9, and then export it under an older format?
Wouldn't that be doable?
Just to add to this thread the links I posted in the other one:
I can't speak to anecdotes like parents' or friend's computers, but in general Flash Player 10 is extremely widely available -- installed on over 95% of the world's desktops & laptops. There are more people still using IE 6 than there are people lacking FP 10. Even in enterprises, which tend to upgrade very slowly, FP 10 is probably on well over 75% of computers by now.
Catalyst projects truly require Flex 4, which truly requires FP 10... there's not much getting around that. If you absolutely must support FP 9, one option is to use Catalyst purely as a mockup/prototyping tool (for user testing, client/executive approval of designs, etc.) and then build the final app from scratch in Flex 3. You won't be able to directly reuse most of the material you created in Catalyst, but it can still be a valuable tool in this workflow -- we've heard from many people that Catalyst lets them create mockups far more quickly than tools they've used in the past.
Hope that helps!