<s:TextArea id="tf"></s:TextArea>

        <s:TextArea id="tf2" x="200" y="200"></s:TextArea>

 

......

 

tf.text = 'Random text is here';

tf2.text = 'HERE IS SOME CAPS TEXT';

for (var i:int = 0; i < tf.textFlow.numChildren; i++) {

        tf2.textFlow.addChild(tf.textFlow.getChildAt(i));

}