static public function sendActivationEmail( $userID )
(...)
        if ( $sendUserMail )
        {
            $templateResult = $tpl->fetch( 'design:user/registrationinfo.tpl' );
            if ( $tpl->hasVariable( 'content_type' ) )
                $mail->setContentType( $tpl->variable( 'content_type' ) );  // <------- used here

            $emailSender = $ini->variable( 'MailSettings', 'EmailSender' );
            if ( $tpl->hasVariable( 'email_sender' ) )
                $emailSender = $tpl->variable( 'email_sender' );
            else if ( !$emailSender )
                $emailSender = $ini->variable( 'MailSettings', 'AdminEmail' );

            if ( $tpl->hasVariable( 'subject' ) )
                $subject = $tpl->variable( 'subject' );
            else
                $subject = ezpI18n::tr( 'kernel/user/register', 'Registration info' );

            $mail = new eZMail();                   <---- initialized here
            $mail->setSender( $emailSender );
            $user = eZUser::fetch( $userID );