Custom_Extension_Model customext_mysql4 Custom_Extension_Model_Mysql4 sometest_test Custom_Extension_Helper Mage_Core_Helper_Data Custom_Extension_Block Custom_Extension core_setup core_write core_read singleton customext/observer customer_load_after singleton customext/observer sales_order_save_before customext.xml Custom_Extension.csv standard Custom_Extension customext singleton customext/observer checkout_cart_add customext.xml Custom_Extension.csv 10 sometestadmin/adminhtml_test/index 10 admin Custom_Extension customextadmin