Add Field SQL ledger accounting

We use SQL ledger as our bookkeeping system. Now we want to use it for our orderentry. Because our produkts come in different colors we want to add a field to the screens for invoice, sales order and purchase order. After entering the sales order we have to be able to generate a purchase order, this is an existing option, containing de details from this field. Can anyone do this for me. And if so, please tell me what details you need. Regards, Nancy