sessions and history

From the moment I started using php4-sessions I got problems with the back- and nextfunctions (history)... It seems that when I click back, my browser doesn't get the previous page from the local cache, but makes a new http-request. If I visited the same page twice, with different values for the parameters, I get the latest values (from the sessionvars).... als when I go back to the first page..... Does anybody recognize this problem and has an answer to it? Thanx in advantage, Rainer. rainer.schreiber@chello.nl