Creating Form in AS3...Can't assign Var Name to Dynamic Text Field?

In AS2 I would simply add a var name to a input text field from the property panel but when I try to do so in AS3 it’s not supported. How do I assign a var name to input text using ActionScript 3? If anyone can answer this for me and/or point me to a thread/tutorial on creating an email form in AS3 I would greatly appreciate it.