Create Flash Movie that Submits Form (POST) in CGI Web Page

I need an existing .CGI web page that is used for a login portal(that has variables in URL string that must be passed) to be modified to force website visitors to first click an "I agree to Terms of Use" form checkbox that then brings up a 30 second flash movie (will be provided) that must be watched entirely before the page then submits some hidden variables and also variables from the URL string to a POST form submit like basic HTML would. I have the form working in HTML, but making this work in flash with JS and CGI is not my forte. This should probably be done with JS, I would imagine there is a way you could create the flash movie to trigger a specific JS function that posts the form variables - this way the variables wouldnt need to be picked up by the flash movie, but if it is easy to do it this way I am open. I can explain exactly what we need a little better over the phone. We would need standard confidentiality agreement signed, FYI.