Sales order number and freight update

We just implemented the transportation module.  I have lost a crucial piece of information after the implementation and was wondering what are other options.

In the past when we entered freight invoices (as a standard voucher) we manually entered in the customer and the sales order that was associated with the expense.  This created a way of reporting on these charges by order and by customer.  Now the only information that I see is the shipment number.

Any ideas that others have used or other options so that we can continue to report freight information based on customer and/or sales order.