Unfortunately, there's no easy way to save a CS5 file as any other version than itself and CS4. I always keep a copy of previous Flash versions in order to be able to save them back to the version I want. It's a cumbersome, but it works. If you can send the file to me I can save it in Flash 8 format and send it back to you again.
Thanks a lot, how do i send you a file??
You can send it to ruidsilva [at] gmail [dot] com.