Extending Objects with a Visible Element

When extending an item with a visible element, e.g. the TextField Object how do you tie in the porperties that would be accociated with it?

for instance, in my class that extends the textfield, i still have to call createTextField (or do i?) do i have to explicitly define each of the properties and tie them to the textfield or is there a way to create the textfield that automatically binds the new tf to the new class?

ooc: if i wanted to create a textfield without using createTextField by using the
var tf:TextField = new TextField(); what would i do to get the physical part to appear?

-Echo