convert SWF files to their FLV format

I need a solution to convert SWF files to their FLV equivalent.
I'm using today ffmpeg to convert other files format like avi and mpeg.

Requirements:
1. convert any swf file to their flv format
2. command line tool
3. cross platform (Windows and Unix)
4. complete. don't just say use xxx program with yyy parameters. I'd like to get the programs and codecs etc. at least for Windows
5. proven. set a simple test form on your server to upload swf file, convert it to flv and view/download the flv so I'll be able to test drive before I buy