Login to forum when logging in externally

[punterzone]

I've seen this mentioned elsewhere but have been unable to replicate it.

I have an external site which is logging into the vB database with no problems. But I would like to have my login script also login to the forum, when it logs into the external site. So if the user switched between sites, they'd be logged into both.

Here is my login script:

PHP Code:

define('START_CWD','/home/pzone/public_html');
define('CWD','/home/pzone/public_html/forum');
chdir(CWD);
include_once CWD.'/includes/class_hook.php';
include_once CWD.'/global.php';
chdir(START_CWD);
include_once('/home/pzone/public_html/forum/includes/functions_login.php');
$password=$_POST['password'];
$username=mysql_real_escape_string($_POST['username']);
$results=mysql_query("SELECT userid,zip,password,salt,dispid FROM com_user WHERE username='$username' LIMIT 1");
$row=mysql_fetch_assoc($results);
$password=md5(md5($password).$row['salt']);
$md5_pass=md5($_POST['password']);
$check=verify_authentication($_POST['username'], '', $md5_pass, $md5_pass, '0', '1');
if($check){
    exec_unstrike_user($username);
    process_new_login('', $username, '');
    $vbulletin->url='/index.php';
    exec_shut_down();
    header('Location:/');
    exit;
}else{
    header('Location:/loginfail');
} 


Is is just a matter of inserting into the "session" table and setting cookies? If so, I'm unsure exactly how to work this, with which cookies to set and the salt etc etc.

Any help would be appreciated!

Thanks