Hi Megha,
What you need to follow is this guide :
Tech Tip : CA Single Sign-On :Policy Server:How to collect additional attribute using custom authentication
However, instead of using the login.fcc form , if you want to use custom login page (say login.jsp) you will need modify the custom login page url in the parameter section as below .
Next, for a sample on how this custom login.jsp can post to login.fcc you need to refer to following :
Custom Login Page
If you need to implement some debugging (which I am sure you will need) for your custom authentication scheme, please refer this :
Tech Tip - CA Single Sign-On:Policy Server:Custom Authentication scheme Debug Logging
Let me know if any questions.
Regards,
Ujwol Shrestha