Using [this guide](http://www.drupalcommerce.org/user-guide/cart) I added a custom line item type to my Drupal Commerce installation and have allowed the customer to add extra data when purchasing an item. When the order is complete I need to get hold of that extra data and use it to build some database rows that will grant them access to the service they have just purchased. I have implemented **hook\_commerce\_checkout\_complete($order)** but I haven't been able to find the data within $order. I know it is there somewhere because I can view the order on the customer's account and have modified the View to show the data next to Unit price, Quantity and Total columns.