sessions and back button

Hi,

I am developing a web site with a section only for registered users and
using sessions to control the access to these pages.
I have the problem with the "back" button of the browsers, especially
in IE.
When I go back within the controlled zone IE always display the message
"page expired" and mozilla displaying the advise that you are trying to
access to a post data page etc..

I am wondering if there is a way to avoid this "problem" a save the
users to think what to do when they see these messages, letting them to
go back and forth until they get out of the session.

Thanks a lot for any help,

Stefano

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