ActionScript 2.0 :: Populating Dynamic TextBox - AutoSize Height

I have the following code to populate a dynamic text box:
Code:
myData = new LoadVars();
myData.onLoad = function() {
trace ("The text box before autosize is: " + sailing_txt._height);
sailing_txt.htmlText = unescape(this.myVariable);
sailing_txt.autoSize = true;
trace ("The text box after autosize is: " + sailing_txt._height);
};
myData.load("sailing.txt");

The output of this is:
The text box before autosize is: 388.25
The text box after autosize is: 712.5

My problem is that I need to get the autosized height instead of the regular height of the text box before autosize. In a parent movie clip I have the following code to do some custom scrolling:
Code:
contentHeight = _parent.scrolledMC.sailing_txt._height;
trace("The content height is: " + contentHeight);

The output of this is:
The content height is: 388.25
So it's getting the size of the text box before it's autosized.