Add field to an AdminCP template?

[Thr33]

I want to add another field in one of the adminCP templates.

To be more specific i want to add another option in the 'paid subscriptions' template. Members can purchase reputation credits which can be used in areas of the site to unlock threads. Currently i must add the rep credits myself when im notified via email. If i was able to add a field in the adminCP for reputation then i could hopefully make it automated.

Im hoping something like this code will work:

PHP Code:

$userid = $vbulletin->userinfo['userid']; 
$newrep = $vbulletin->userinfo['reputation']+['x']; 
$vbulletin->db->query_write("UPDATE user SET reputation=".$newrep." WHERE userid=".$vbulletin->userinfo['userid']); 


Any help would be great, thank you.