AddCustomHeader – SMTP user

Ciao

with the old versions we used to add a custom header via function.php.

    add_filter('wp_mail_smtp_custom_options','my_wp_mail_smtp_custom_options');

    function my_wp_mail_smtp_custom_options($phpmailer) {	
            $phpmailer->AddCustomHeader("Qadisha-Form: " . get_option('smtp_user'));
            return $phpmailer;
    }   

I just realize that 1.2.5 returns NULL for get_option(‘smtp_user’). Could you please let me know the option that replace smtp_user?

Thanks
Antonino