Changing text size via actionScript

Could someone please direct me in how to change text size with actionScript.

I have gone through the help and am able to change other properties, such as bold using actionScript, but I haven’t been able to do so with text size.

The scene will have 2 buttons – a plus and minus button. Upon clicking the plus button the text gets bigger, and smaller with the minus button.

I have figured from the help that to access the text properties you must create a new text object construct by doing this:

myTextFormat = new TextFormat();
myTextFormat.bold = true;
myTextField.setTextFormat (myTextFormat);

now a property of the text box is .size – I thought you would be able to simply say myText.text.size = 12; or myText.size = 12;

Does anyone have a solution?

Thanks

Joshua