Java EE (Java Enterprise Edition) General Discussion

In our application we are using the siteminder for the authentication of the users. Whenever the user is authenticated by the siteminder the user is being taken to the application welcome page.Then user performs his own activities and after that whenever he is logging out, i am taking him to the logout page and before that i am clearing all the sessions using the session.invalidate and also setting the session = null. I porvide a link the logout page where the user can click to relogin to the application. So whenever the user clicks on it he should be prompted with the siteminder login screen, instead it is directly taking me to the application. So i dont know wht to do. But if i close the window and open the new window i am getting that login prompt.But when the users types the same URL in the same page he is taken into the application without login screen

Please help me with this issue