As I am building a Flex framework for minigames, I plan to bundle a bunch of graphic assets (movieclip symbols) into a single swf file, which I will load into my Flex application, before extracting the symbols from the swf file for use in my application. My question is this: how do I do this through actionscript?
If you don't want to use EMBED and you don't want to load the assets on runtime I recommend you exporting the swf as an SWC.
This way, you can browse SWC files from actionscript. You can event check on compile time that a sub-movieclip inside another movieclip exists.
If you are using flex compiler then remember adding this when you compile:
If you're using FDT you have an option to auto add the SWC as arguments.
Here's a demo on how to do it with FDT. Not sure which tool are you using. If it's the commercial Flex Builder the process should be similar.
I think that's what you're looking for.