Magento – Top navigation menu stopped displaying

Starting with Magento CE 1.7 there is this event available page_block_html_topmenu_gethtml_before that allows you to add any items to the top menu.
For example it is used to add the categories to top menu in Mage_Catalog_Model_Observer::addCatalogToTopmenuItems().
The only constraint is that your top menu block should look like this in page.xml

<block type="core/text_list" name="top.menu" as="topMenu" translate="label">
    <label>Navigation Bar</label>
    <block type="page/html_topmenu" name="catalog.topnav" template="page/html/topmenu.phtml"/>
</block> 

If your theme is somehow similar with the default theme for 1.7 you should be able to add links to the top menu using this event.
Note: in 1.7 the top menu is rendered by this template: page/html/topmenu.phtml.

$_category = Mage::getModel('catalog/category')->load(CATEGORY-ID);    
    $_categories = $_category
                    ->getCollection()
                    ->addAttributeToSelect(array('name', 'image', 'description'))
                    ->addIdFilter($_category->getChildren());

    foreach ($_categories as $_category):
       echo $_category->getName();
    endforeach;