Unable to auomate SWF component using Selenium
There is a Selenium-Flex API. I believe it requires instrumenting your swf files so that their controls are actually called by JavaScript, but includes a tool for doing that instrumentation.
I have not tried this, but might when I have some time...
EDIT:
Just noticed you referenced it not working for you in comments already. If you need to call it from perl it may indeed be impossible. I'd have to be a real user of it to know.
I encountered the same problem in automating a flash uploader widget in my own tests. Unfortunately, selenium cannot be used to automate run-of-the-mill flash SWF files.
If you want to upload something, then throw a script up on your server to which you can POST file data, and POST the data directly from your script (I am assuming that you are running selenium-rc). In any case, this is just working around the flash widget.