This has been a complaint since CS4. Maybe you finally fixed it in CS5.5? I'm in CS5, and cannot copy a group of layers with the "copy frames" option as I would with any other layer(s). So a bone tool animation I've done on the main timeline cannot be copied and turned into a mc symbol. A simple, basic process. I can export my MC and import, then it comes in as stills, increases file size, not editable.
I'm sure the answer is "plan ahead." The answer should be, "Of course you can do that, that's always been a normal method of working in Flash."
Flash is dieing as a web tool, and falling short as an animation tool.
Can you show me the .fla file or whatever?