I have been using this work flow for sometime. I hand animate a sequence or a still of a character in Flash Pro on a single timeline, no scipts, etc just clean keayframe animation or a single frame.
Then export the sequence as a .swf.
Then usually import it into After Effects and use the vector output in my AE scene.
After completeing an animatic for a client last week all the swf's in my AE project are EMPTY. I tried re-exporting from flash and reimporting into AE and again they show up 1st time but if I close and reopen the project they are GONE again!!! Help I have been doing this same process since CS4 and I have master animations in AE files that I'm now scared to death to open because AE will make my work vanish...