Billing Interface - prepaid amount field value

Hi,

    Can anyone guide me like - INTFC_BI_HDR - PAID_AMOUNT field value is empty in IINTFC_BI_HDR table. however once the Billing Interface process completes and once worksheet approved the value for PAID_AMT is stored rightly in BI_HDR table. INTFC_BI table also doesnt have that field at all.

Details:

            To import prepayment information into PeopleSoft Billing through the billing interface, you must populate the PAID_AMT and the PAID_REFERENCE fields in the Billing Interface Header table (INTFC_BI_HDR). PeopleSoft Billing does not validate the data in the billing interface; you must validate prepayment information in the source system before you pass the data to PeopleSoft Billing.