[backwards compatibility] [mustella] paddingLeft & paddingRight default to 0 instead of 3 (Flex 2.0.1)

Reproduction:
1. Compile & run the following with Flex 2.0.1 and Flex 3
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Canvas id="myCanvas" height="150" width="300">
<mx:VBox>
<mx:CheckBox id="myCheckBox"/>
<mx:Label text="paddingLeft

"/>
<mx:Label text="paddingRight

"/>
</mx:VBox>
</mx:Canvas>
</mx:Application>

Actual Results:
In Flex 2.0.1 paddingLeft & paddingRight default to 3. In Flex 3 paddingLeft & paddingRight defaults to 0.

Expected Results:
paddingLeft & paddingRight should default to 3 according to the documentation.

Workaround:
None.