How to Pass Username as a parameter in webdynpro URL

Hello Techies,

I need yours help..

I want to know how i pass username and password in webdynpro abap  application link so that i use in browser without log in it.

I go through many link , as per them pass parameters in url(eg.  matnr=0111101000), and handle in the  HANDLEDEFAULT method of window controller.

but HANDLEDEFAULT of window controller is assessable only after log in .

Please suggest the way to resolve this.