How to switch Tab with animation?

Hi, Im new to Titanium and have a question.

How to switch Tab with animation?

My situation is;

1. TabGroup is hidden.

2. got a button to change tab by adding event. the eventListener of the button is like this;

   theButton.addEventListener(click, function()
   {
       tabGroup.tab[0].active = true;
   });

   I'd like to add animation this event but how...

thanks.