flex 4 autosize text

I have a grid of text boxes in my Flex 4 app that loads an xml file and displays whatever is written there. The number of boxes won't change, but the text inside them will. This is a sign that needs to be readable from a distance so I need the font to autosize to fit. So it should go large if it can, if not, it should be just large enough to display what's in the box.

I've tried RichText, RichEditableText, and TextArea and not开发者_高级运维hing seems to work. The other posts on autosizing text at Stackoverflow weren't helpful either. Does anyone know how to do this?