how to regenerate your own session id

There is a function called, session_regenerate_id, for php4.3.2 and above. Right now, it just creates a random id. Is there a way to specify the value of the regenerated session_id? So I can record the SID before I send out every time. I tried, session_id('id_generated_me'); session_start(); This code does write a new SID, but it also resets the session. Which means I can't get the data set in the previous session. I also tried, session_start(); setcookie(session_name(), SID_generated_by_me ); believe it or not, this just puts another cookie in the client browser with same "session_name". (I didn't even know that 2 cookies from the same domain, with same session name is possible, I thought one would just replace the other) And the session is still reading from the old cookie with the old SID. I search through the doc, but have no luck. Any suggestion appreciated. Thanks. Tree