Had a quick look at that http://buildingmyworld.wordpress.com/ link I mentioned in previous post.
As below, it works like magic! First it shows this full screen covered in orange colour. If you move your finger/mouse pointer around, it will "scratch" off the orange colour and reveal the nice Apple image below.
The source code is also available on that blog. Thanks for the sharing and it's definitely much better than mine. The best part is - everyone knows how to do it now, ha ha!