FormsAuthentication does not prevent Back button from showinf accessed pages

From: smrity jain (smrityj@yahoo.com)
Date: 10/30/02 

From: "smrity jain" <smrityj@yahoo.com>
Date: Tue, 29 Oct 2002 15:29:46 -0800

Hi All,
I am using FormsAuthentication.It works great with one
exception,
when a user logs out i say formsauthentcation.SignOut and
redirect to login page.
Now if i click on browser back button previous secured
page is displayed.

i tried following work arounds but none work
1. access the histor list, its is secured so no access
priviledges are availabe
2.
Response.Cache.SetCacheability(HttpCacheability.NoCache);
does not work when written just before
formsauthentcation.SignOut.

please help ASAP

regards
sj.