Syntax for dynamically creating Custom Classes

Hi there, I am trying to load 4 custom classes from my library that are movieclip symbols and I want to be able to do this dynamically without having to hard-code each instance.

At the moment I am writing the code like this:

[AS]
var my1:S1 = new S1();
var my2:S2 = new S2();
var my3:S3 = new S3();
var my4:S4 = new S4();

function addMys() {
for (var i=0; i<4; i++) {
var myS:Sprite = this[“my”+(i+1)]
this.addChild(myS);
}
}
[/AS]

I would like to create the instances of the sprites within my loop but I’m not sure of the syntax, if someone could show me how to write this I would be really grateful.
Thanks!

Schm