загруженное имя файла в теме письма

Ниже кода будет показано имя файла в теле письма, но я хочу, чтобы оно также отображалось в теме письма.
Где я положу $ files_list в тему?

Я старался

 'subject'  => __('$files_list uploaded for you','cftp_admin')
'subject'  => __($files_list.'New files uploaded for you','cftp_admin'),

Не работает. Вот код:

$email_strings_file_by_user = array(
'subject'   => __('New files uploaded for you','cftp_admin'),
'body'      => __('The following files are now available for you to download.','cftp_admin'),
'body2'     => __("If you prefer not to be notified about new files, please go to My Account and deactivate the notifications checkbox.",'cftp_admin'),
'body3'     => __('You can access a list of all your files or upload your own','cftp_admin'),
'body4'     => __('by logging in here','cftp_admin')
);function email_new_files_for_client($files_list)
{
global $email_strings_file_by_user;
$this->email_body = $this->email_prepare_body('new_file_by_user');
$this->email_body = str_replace(
array('%SUBJECT%','%BODY1%','%FILES%','%BODY2%','%BODY3%','%BODY4%','%LINK%'),
array(
$email_strings_file_by_user['subject'],
$email_strings_file_by_user['body'],
$files_list,
$email_strings_file_by_user['body2'],
$email_strings_file_by_user['body3'],
$email_strings_file_by_user['body4'],
BASE_URI
),
$this->email_body
);
return array(
'subject' => $email_strings_file_by_user['subject'],
'body' => $this->email_body
);
}