function makeCallable(flashObj, methodName) {
   flashObj[methodName] = 
      (function(methodName) {
         return function() {
            this.CallFunction(
               '<invoke name="' + methodName + '" returntype="javascript">'
                  + __flash__argumentsToXML(arguments, 0)
               + '</invoke>');
         }; // dangling semi-colon for IE 6
      })(methodName); // force re-closure to prevent IE memory leaks
}
Exposes the given methodName on the given flashObj to make it callable, without
    using an eval() to speed things up. Note that only strings therefore can be passed
    _back_ from Flash, though complex types can be passed from JavaScript to Flash.