Setting User agent ?

I am making a small AIR app that shows an HTML page. How do I set the user agent ?
I do not want to use the default one. I went through this: http://help.adobe.com/en_US/AIR/1.1/devappsflex/WS5b3ccc516d4fbf351e63 e3d118666ade46-7e7b.html

But a sample code or explanation would be good.