I found one more easier way to communicate with back end system with client using ruby on rails and flash when I was working with one of my rubystar guy. Now one more way of ajaxing easily.
<div id="myFlash"> Some text for google serach engine </div>
var currentTime = new Date();
// this is avoid catching when append with flash files
var filePath = "/myFlash.swf?"+currentTime.getSeconds();
var foo= new SWFObject(filePath, "tutor", "683", "400", "8");
foo.addVaraible("flash Variable", "<%= variable %>" )
//your flash variable will updated with ruby variable