Ref Interest Rate as of last day of the month !!

Hello folks,

Quick & Simple question:

Reference Interest Rates are only available as of LAST WORKING DAY of the month.

But for the loan instruments that require interest upto LAST DAY of the month requires the Ref Interest Rates to be available on that LAST DAY of the month.

TJ05 - Automatic update of Ref Interest Rate requires the rate to be available on Fixing day itself means as of  LAST DAY of the month while we only have rates as of Last Working Day of the month.

How is this handled OUT-OF-BOX in SAP?

At one of my client, they had the Ref Interest rate on Last Working Day populate the last day of the month too via a customization in the interface program that handled BB file.

Please advise!!

Rahul