Вау! заработало при такой комбинации! :)
<fx:Declarations>
<s:Rotate id="rotate"
target="{img}"
angleFrom="{angle - 90}"
angleTo="{angle}"
duration="0"
autoCenterTransform="true"
/>
</fx:Declarations>
<s:Button x="334" y="338" label="Button" click="button1_clickHandler(event)"/>
<s:Group x="159" y="214" width="159" height="86">
<s:Group width="100%" height="100%" >
<s:Image id="img" width="100%" height="100%" horizontalCenter="0" scaleMode="letterbox"
smooth="true" smoothingQuality="high" source="@Embed(source='site.png')"
verticalCenter="0"/>
</s:Group>
</s:Group>