//This function is called from Flash (when one of the buttons is clicked) via ExternalInterface.call();
//sendMessage(); calls a function that belongs to an instance
//the firts parameter is the name of the target instance in Unity, next the name of the function we want to call, and finally, the parameter to send.
GetUnity().SendMessage(“UnityCube”, “moveCSharp”, direction);
//This function is called from Unity (when the cube is clicked) via Application.ExternalCall();
//check how to call the ActionScript function depnding on the OS
if (navigator.appName.indexOf(“Microsoft”) != -1)
You can check the example (and source) here.