Update vbulletin setting array !

[K a M a L]

Welcome all ;
I'm creating an admin page to control setting of a plugin
I use a query

PHP Code:

$db->query_write("UPDATE " . TABLE_PREFIX . "setting
                SET value = ".$recusergroup."
                WHERE varname  ='reccreate2'"); 


the setting is updated in setting table but when I call

PHP Code:

$vbulletin->options['reccreate2'] 


I get the old value not the updated one
I think the setting is cached somewhere or stored at another table
my question is what to do to update the setting