Frame for form login

[TWR - Hauptuser]

Hello,

I am using form based login for my web application and after some 
difficulties everyting works fine - well, almost everything: I am using 
frames in my web app and after timeout the login page login.jsp always 
appears in the current frame not in a top window (like <a href="..." 
target=_parent"). How can I achieve this? Writing login.jsp target=_parent in 
the web.xml doesn't work. Any idea?

Thank you in advance

Thomas