Importing Flash Assets to Flex a AS Project

So I’ve long been developing in flash, but I am currently working on a project that need to be developed using flex. That is to say, it is actually not a flex project (MXML) but rather an ActionScript project in flex. The transition has been pretty smooth thus far but now I’m stuck. I have a flash CS3 file with a document class that functions correctly. There are a number of movie clips that are on the stage and are targeted by the AS by referencing there instance names (they exist on stage). I’m wondering what the best approach is to get all the movieclip assets into flex is, I looked online, but everone seems to have a different way. Some people use SWCs some export the swf with all the MCs set to export, and others turn the entire flash movie into a component then import that to flex . . . . any advice?