sendAndLoad from within on(release)

programming flash
1 

// within a movieclip
on(release) {
     
     // code that launches an input box containing another button
     ////////////////////////////////////////////

     myInputBox.btnGo.onPress = function () {
          myURL = 'filename.php';
          myVars = new LoadVars();
          myVars.sendAndLoad(myURL, myVars, 'post');
         
          // this part won't work... I guess I can't declare functions within others...
          myVars.onLoad = function() {
                    // extract the LoadVars data... but I can't
          };
 
};

}

How can I get the values of myData from within a nested function? Or, how can find out when the loadvars have loaded from outside the myInputBox.btnGo.onPress function?

Thanks in advance