[horde] Administrator account case insensitive log-in

[Kenren Taisho]

Hi.
Is it possible for administrator accounts to log-in case insensitive?
I do have the following in IMP's hooks.local.php

public function preauthenticate($userId, $credentials)
>       {
>  return array(
>                  'userId' => Horde_String::lower($userId),
>                  'credentials' => $credentials
>          );
>           return true;
>       }


and user log-in work regardless of the letter case, however, Administrator
accounts lose their administrator privileges when logging in on the wrong
letter case.

Example: If the administrator account is super.user
super.user <-- Ok
Super.user <-- Can log in Ok, but no admin privilege.

Thanks and kind regards!