session cookie lifetime

I would like to have multiple session cookie lifetime lengths. For example in my php.ini file I have: session.cookie_lifetime = 300 (5 minutes) This works perfectly fine in my code. My problem occurs when I try to use session_set_cookie_params in my code to set the cookie lifetime to a longer time. I would like to have some pages/users have a longer cookie lifetime. When I echo out the cookie lifetime using session_get_cookie_params after setting it to say 8 hours I get the correct value, but the actual cookie is expiring after 5 minutes (what the php.ini file says). When should I be running the session_set_cookie_param function? Thanks in advance, -- Brent Edwards