invoice and allocated cost

Hi,

version : 6.3.1

I have an invoice with 3 LI(all for accessorials code) and approved and thus created voucher. voucher is allocated also at ORL type. Per Invoice Line item, the correspondent ORL Id's are mapped and allocation is purely on piece count basis. Now there is a need to send few of the invoice header level information and along with for every LI, the corresponding allocated cost per invoice LI-ORL id combination(typically we can see when we run allocate voucher) to middleware(outbound from OTM) via httppost. please let me know how can I achieve that? what should be my XML element ID,