I have a script that saves information to a session 
variable and then sends the session_id to another script 
via POST, which does something, then sends data to another 
PHP script by silent POST, including the session_id, which 
is to retrieve the original values saved in the session, 
specified by it's original session_id.

1st PHP script:
$USER_FORM = "a bunch of text";

session_register("USER_FORM");

$sess = session_id();

exit;


2nd PHP script:
/* We want to start our session from a session id that is 
passed
	to us in POST data */
$sess = $HTTP_POST_VARS['sess'};

ini_set("session.auto_start", "0");
ini_set("session.cache_limiter", "public");

session_id($sess);
session_start(); 

global $USER_FORM;

/* Instead of printint the "bunch of text", it prints 
nothing */
print $USER_FORM;


This same code worked using PHP 4.0.6 running on UNIX.


In my php.ini, I have session_auto_start set to true, which 
is why I turn it off by setting the ini in the 2nd script.
Register globals is on.