How to import Blanket Purchase Agreement distribution line in R12.2.6

Hi,

Do any one have idea regarding importing of distribution line for Blanket Purchase agreement. We are using R12.2.6 where we can book encumbrance for BPA through encumbrance tab available in the front end. But we have business requirement of creating BPA through back end . While creating BPA through interface table, only header and line tables are getting populated not the distribution table.

Quick response will be highly appreciated.

Attaching the code:

------------------Header----------------------

Insert into PO.PO_HEADERS_INTERFACE

    (INTERFACE_HEADER_ID,

     BATCH_ID,

     PROCESS_CODE,

     ACTION, 

     ORG_ID,

     DOCUMENT_TYPE_CODE, 

     CURRENCY_CODE,

     AMOUNT_AGREED,

     AGENT_ID, 

     VENDOR_ID,