You'll need to use Flash Professional to produce a component with a proper registration point and export that component in a SWC. You're correct that there isn't a straightforward way to do this via ActionScript that I know of that doesn't involve transform matrix.
Jason San Jose
Software Engineer, Flash Builder
Why isn't there a programmatic way to set the registration point? And what exactly do you mean by transform matrix? I need to learn how to do this directly from Flash Builder. It would be fun to play with Flash Professional too, but I want a solution from within the application.