You might want to take a look at
Automated UI Tester For ActionScript[
^]. It says on that page that " ... Works on web-based apps and standalone SWF files. ..." so it should work for you too.
[Edit]Not sure it will be useful to you as it is an eclipse plugin. One could learn from the source code of course, but that may prove a bit tedious. :)
[/Edit]
Cheers!