I already understand that you are able to communicate to your embedded flash application using JavaScript.
My question is: Assume I have a flash button and a flash form in the same PDF, can I talk directly from the button to the form by a call directly to an ActionScript method? Or is actionscript/javascript and then javascript/actionscript the only way?
You might be able to open a socket from actionscript in each SWF so they can talk to each other, you would likely encounter a security warning/dialog with this method and I don't know if it would work but it may be worth looking into.