<?php
class Orange35_Local_Block_Navigation extends Mage_Catalog_Block_Navigation {
    public function getCurrentChildCategories()
    {
        $layer = Mage::getSingleton('catalog/layer');
        $category   = $layer->getCurrentCategory();
        /* @var $category Mage_Catalog_Model_Category */
        $collection = Mage::getModel('catalog/category')->getCollection();
        /* @var $collection Mage_Catalog_Model_Resource_Eav_Mysql4_Category_Collection */
        $collection->addAttributeToSelect('url_key')
            ->addAttributeToSelect('name')
            ->addAttributeToSelect('is_anchor')
            ->addAttributeToSelect('image')
            ->addAttributeToFilter('is_active', 1)
            ->addIdFilter($category->getChildren())
            ->setOrder('position', 'ASC')
            ->joinUrlRewrite()
            ->load();

        $productCollection = Mage::getResourceModel('catalog/product_collection');
        $layer->prepareProductCollection($productCollection);
        $productCollection->addCountToCategories($collection);
        return $collection;
    }
}