back button problem

[eluser]dimis[/eluser]
I have a locked section and I have the problem when user use the back button of IE and firefox the page is here as he did no lock out.
I use the

Code:

header('Cache-Control',
'no-store, no-cache, must-revalidate');
header('Expires', '-1');
header('Pragma', 'no-cache');

at header view.
and the html related tags.
I have a xamplite setup firefox 2 and IE 5.5
Dimis