woocommerce_admin_order_preview_start action-hook . WC 1.0

Usage

add_action( 'woocommerce_admin_order_preview_start', 'action_function_name_8508' );
function action_function_name_8508(){
	// action...
}

Where the hook is called

<?php do_action( 'woocommerce_admin_order_preview_start' ); ?>

Where in WP core the hook is used WooCommerce