cookie problem. Not possible to set and read a cookie on the same page?

Hi there, I am wondering if it is possible to send a cookie and read it on the same page. Following environment: There is a cookie already on the machine of the client, but expired. Now I am setting a new cookie and reading it on the same page via $sess_id = $HTTP_COOKIE_VARS[$sesscookiename]; Unfortuanaelly it gives me the old session id back. After refreshing I am getting the new sessid and everything works fine. The cookie has been sent with the right value, I did dubble check it. But the HTTP_C... reads the old one. why? Thanx for any help, Andy