Enforce reloading of page when using the back-button

Hi,

Is there a way to make the browser reload a page from server when the
back-button is used. I have tried the "Pragma", "Cache-control" and
"Expires" headers, but it doesn't prevent the browser from loading the page
from cache when the back-button is used. (for example IE5 does load it from
cache). I would like to avoid this in some cases, and have the browser to
send a new request so the server could determine if the user is still logged
in (ie hasn't clicked any logout button on a page), and if not, show a not
logged in page, rather than the previos content of the page.

Is this possible? Thanks a lot in advance!

Christian