CheckoutPage::getCMSFields PHP Method

    public function getCMSFields()
    {
        $fields = parent::getCMSFields();
        $fields->addFieldsToTab('Root.Main', array(HtmlEditorField::create('PurchaseComplete', _t('CheckoutPage.db_PurchaseComplete', 'Purchase Complete'), 4)->setDescription(_t('CheckoutPage.PurchaseCompleteDescription', "This message is included in reciept email, after the customer submits the checkout"))), 'Metadata');
        return $fields;
    }