_config.php

<?php
// Extentions
SiteConfig::add_extension('Ext_Commerce_SiteConfig');
Image::add_extension('Ext_Commerce_Image');
Controller::add_extension('Ext_Commerce_Controller');
Group::add_extension('Ext_Commerce_Group');
Member::add_extension('Ext_Commerce_Member');

if(class_exists('Users_Account_Controller')) {
    Users_Account_Controller::add_extension('Ext_Commerce_UsersController');
}

// If subsites is installed
if(class_exists('Subsite')) {
    Product::add_extension('Ext_Subsites_CommerceObject');
    ProductCategory::add_extension('Ext_Subsites_CommerceObject');
    Order::add_extension('Ext_Subsites_CommerceObject');
    CatalogueAdmin::add_extension('SubsiteMenuExtension');
    LocaliseAdmin::add_extension('SubsiteMenuExtension');
    OrderAdmin::add_extension('SubsiteMenuExtension');
}

LeftAndMain::add_extension('Ext_Commerce_LeftAndMain');

// Setup google sitemaps
if(class_exists("GoogleSitemap")) {
    GoogleSitemap::register_dataobject('Product');
    GoogleSitemap::register_dataobject('ProductCategory');
}