Добавление новой вкладки к странице просмотра заказа, не отображаемой в Magento

Вот мой конфигурационный файл:

<?xml version="1.0"?>
<!--
/**
* MageWorx
* Admin Order Editor extension
*
* @category   MageWorx
* @package    MageWorx_OrdersEdit
* @copyright  Copyright (c) 2015 MageWorx (http://www.mageworx.com/)
*/
-->
<config>
<modules>
<MageWorx_OrdersEdit>
<version>2.0.3</version>
</MageWorx_OrdersEdit>
</modules>
<admin>
<routers>
<adminhtml>
<args>
<modules>
<MageWorx_OrdersEdit after="Mage_Adminhtml">MageWorx_OrdersEdit_Adminhtml</MageWorx_OrdersEdit>
</modules>
</args>
</adminhtml>
</routers>
</admin>
<global>

<events>
<sales_convert_order_item_to_quote_item>
<observers>
<mageworx_ordersedit_convert_order_item_to_quote_item>
<class>mageworx_ordersedit/observer</class>
<method>convertOrderItemToQuoteItem</method>
</mageworx_ordersedit_convert_order_item_to_quote_item>
</observers>
</sales_convert_order_item_to_quote_item>
<sales_convert_order_to_quote>
<observers>
<mageworx_ordersedit_convert_order_to_quote>
<class>mageworx_ordersedit/observer</class>
<method>convertOrderToQuote</method>
</mageworx_ordersedit_convert_order_to_quote>
</observers>
</sales_convert_order_to_quote>
<sales_quote_collect_totals_after>
<observers>
<mageworx_ordersedit_quote_collect_totals_after>
<class>mageworx_ordersedit/observer</class>
<method>quoteCollectTotalsAfter</method>
</mageworx_ordersedit_quote_collect_totals_after>
</observers>
</sales_quote_collect_totals_after>
<adminhtml_sales_order_create_process_data>
<observers>
<mageworx_ordersedit_order_create_process_data>
<class>mageworx_ordersedit/observer</class>
<method>orderCreateProcessData</method>
</mageworx_ordersedit_order_create_process_data>
</observers>
</adminhtml_sales_order_create_process_data>
<core_collection_abstract_load_before>
<observers>
<amflags>
<type>disabled</type>
</amflags>
</observers>
</core_collection_abstract_load_before>
</events>

<blocks>
<mageworx_ordersedit>
<class>MageWorx_OrdersEdit_Block</class>
</mageworx_ordersedit>
<adminhtml>
<rewrite>
<sales_order_view>MageWorx_OrdersEdit_Block_Adminhtml_Sales_Order_View</sales_order_view>
</rewrite>
</adminhtml>
</blocks>

<models>
<sales_mysql4>
<rewrite>
<order_status_history_collection>MageWorx_OrdersEdit_Model_Resource_Order_Status_History_Collection</order_status_history_collection>
</rewrite>
</sales_mysql4>
<salesrule>
<rewrite>
<quote_discount>MageWorx_OrdersEdit_Model_SalesRule_Quote_Discount</quote_discount>
</rewrite>
</salesrule>
<payment>
<rewrite>
<method_ccsave>MageWorx_OrdersEdit_Model_Payment_Method_Ccsave</method_ccsave>
</rewrite>
</payment>
<paypal>
<rewrite>
<payflowpro>MageWorx_OrdersEdit_Model_Paypal_Payflowpro</payflowpro>
<direct>MageWorx_OrdersEdit_Model_Paypal_Direct</direct>
<api_nvp>MageWorx_OrdersEdit_Model_Paypal_Api_Nvp</api_nvp>
</rewrite>
</paypal>
<paygate>
<rewrite>
<authorizenet>MageWorx_OrdersEdit_Model_Paygate_Authorizenet</authorizenet>
</rewrite>
</paygate>
<sales>
<rewrite>
<order_payment>MageWorx_OrdersEdit_Model_Sales_Order_Payment</order_payment>
</rewrite>
</sales>
<ordertags>
<rewrite>
<observer>MageWorx_OrdersEdit_Model_AwOrdertags_Observer</observer>
</rewrite>
</ordertags>

<mageworx_ordersedit>
<class>MageWorx_OrdersEdit_Model</class>
<resourceModel>mageworx_ordersedit_resource</resourceModel>
</mageworx_ordersedit>

<mageworx_ordersedit_resource>
<class>MageWorx_OrdersEdit_Model_Resource</class>
<entities>
<upload_files>
<table>mageworx_ordersedit_upload_files</table>
</upload_files>
</entities>
</mageworx_ordersedit_resource>
</models>

<helpers>
<mageworx_ordersedit>
<class>MageWorx_OrdersEdit_Helper</class>
</mageworx_ordersedit>
</helpers>

<resources>
<mageworx_ordersedit_setup>
<setup>
<module>MageWorx_OrdersEdit</module>
<class>MageWorx_OrdersEdit_Model_Resource_Setup</class>
</setup>
<connection>
<use>core_setup</use>
</connection>
</mageworx_ordersedit_setup>
<mageworx_ordersedit_write>
<connection>
<use>core_write</use>
</connection>
</mageworx_ordersedit_write>
<mageworx_ordersedit_read>
<connection>
<use>core_read</use>
</connection>
</mageworx_ordersedit_read>
</resources>

<template>
<email>
<mageworx_ordersedit_email_order_comment_template translate="label" module="mageworx_ordersedit">
<label>Order Edit</label>
<file>mageworx/ordersedit/mageworx_order_edited.html</file>
<type>html</type>
</mageworx_ordersedit_email_order_comment_template>
<mageworx_ordersedit_email_order_comment_guest_template translate="label" module="mageworx_ordersedit">
<label>Order Edit for Guest</label>
<file>mageworx/ordersedit/mageworx_order_edited_guest.html</file>
<type>html</type>
</mageworx_ordersedit_email_order_comment_guest_template>
</email>
</template>

<sales>
<order_invoice>
<totals>
<mageworx_ordersedit>
<class>mageworx_ordersedit/sales_order_invoice_total</class>
<after>tax,grand_total</after>
</mageworx_ordersedit>
<subtotal>
<class>mageworx_ordersedit/sales_order_invoice_subtotal</class>
</subtotal>
<mageworx_ordersedit_shipping>
<class>mageworx_ordersedit/sales_order_invoice_shipping</class>
<after>shipping</after>
</mageworx_ordersedit_shipping>
</totals>
</order_invoice>
</sales>
</global>

<adminhtml>
<layout>
<updates>
<mageworx_ordersedit>
<file>mageworx_ordersedit.xml</file>
</mageworx_ordersedit>
</updates>
</layout>
<events>
<core_block_abstract_to_html_after>
<observers>
<mw_add_coupon_block>
<type>singleton</type>
<class>mageworx_ordersedit/observer</class>
<method>insertCouponBlock</method>
</mw_add_coupon_block>
</observers>
</core_block_abstract_to_html_after>
</events>
<translate>
<modules>
<MageWorx_OrdersEdit>
<files>
<default>MageWorx_OrdersEdit.csv</default>
</files>
</MageWorx_OrdersEdit>
</modules>
</translate>
</adminhtml>

<default>
<mageworx_ordersmanagement>
<ordersedit>
<enabled>1</enabled>
<enable_shipping_price_edition>1</enable_shipping_price_edition>
<show_thumbnails>1</show_thumbnails>
<thumbnail_height>50</thumbnail_height>
<send_update_email>0</send_update_email>
<hide_edit_button>1</hide_edit_button>
<show_all_states_in_history>0</show_all_states_in_history>
</ordersedit>
</mageworx_ordersmanagement>
</default>

</config>

Вот мой layout.xml:

<?xml version="1.0"?>
<!--
/**
* MageWorx
* Admin Order Editor extension
*
* @category   MageWorx
* @package    MageWorx_OrdersEdit
* @copyright  Copyright (c) 2015 MageWorx (http://www.mageworx.com/)
*/
-->
<layout>
<adminhtml_sales_order_view>

<reference name="avans_tabs">
<action method="addTab"><name>avans_tab</name><block>mageworx_ordersedit/adminhtml_order_view_tab_avans</block></action>
</reference>

</adminhtml_sales_order_view>

<mageworx_ordersedit_order_history>
<block type="mageworx_ordersedit/adminhtml_sales_order_history" name="order_history" template="mageworx/ordersedit/sales-order-view-history.phtml" output="toHtml"/>
</mageworx_ordersedit_order_history>

<adminhtml_mageworx_ordersedit_history_addcomment>
<update handle="mageworx_ordersedit_order_history" />
</adminhtml_mageworx_ordersedit_history_addcomment>

<adminhtml_mageworx_ordersedit_history_deletehistory>
<update handle="mageworx_ordersedit_order_history" />
</adminhtml_mageworx_ordersedit_history_deletehistory>

<adminhtml_mageworx_ordersedit_history_saveeditcomment>
<update handle="mageworx_ordersedit_order_history" />
</adminhtml_mageworx_ordersedit_history_saveeditcomment>

<adminhtml_sales_order_invoice_new>
<reference name="invoice_totals">
<block type="adminhtml/sales_order_totals_item" name="ordersedit" template="mageworx/ordersedit/invoice_totals.phtml" />
</reference>
</adminhtml_sales_order_invoice_new>
</layout>

Вот мой: /MageWorx/OrdersEdit/Block/Adminhtml/Order/View/Tab/Avans.php:

<?php
class MageWorx_OrdersEdit_Block_Adminhtml_Order_View_Tab_Avans
extends Mage_Adminhtml_Block_Template
implements Mage_Adminhtml_Block_Widget_Tab_Interface
{
protected $_chat = null;

protected function _construct()
{
parent::_construct();
$this->setTemplate('ordersedit/order/view/tab/avans.phtml');
}

public function getTabLabel() {
return $this->__('Tab label');
}

public function getTabTitle() {
return $this->__('Tab title');
}

public function canShowTab() {
return true;
}

public function isHidden() {
return false;
}

public function getOrder(){
return Mage::registry('current_order');
}

Вот мой: /app/design/adminhtml/default/default/template/mageworx/ordersedit/order/view/tab/avans.phtml:

<div class="entry-edit">
<div class="entry-edit-head">
<h4><?php echo $this->__('Hello its me!'); ?></h4>
</div>
<div class="fieldset fieldset-wide">
the content you want to show
</div>
</div>

Я пытаюсь добавить новую настраиваемую вкладку на страницу просмотра заказа в панели администратора, но ничего не появляется.

Где моя ошибка?