Balance Forward Billing - Is there a way to add additional fields to show on the bill to customer

We use Consolidated Billing Invoice in 11.5.10.2 and are upgrading to R12 (12.1.3). As we all know that oracle has changed the name from CBI to Balance Forward Billing and uses BPA for this. In 11i we have the flexibility to customize the CBI and add additional fields to show on the report when we print. For example, BOL #, customer PO # etc.

I understand that this flexibility is not available for BFB. We can't add Supplementary Data Source like in BPA for Invoices. The out of the box BFB has all the fields that I need with the exception of 3 very important fields. They are interface_line_attribute4, interface_line_attribute8 from RA_CUSTOMER_TRX_LINES_ALL table and purchase_order from RA_CUSTOMER_TRX_ALL. I would like to know  if any BFB users had this kind of requirement and found any work around to add the additional fields.