Error status 51 no revere entry provided for Inbound IDOC FIDCCP01

hi experts ,

I am receiving an INCOUND IDOC from Sap XI Server .I have given the segements below but my question is if the @nd line item is given while receiving how do i post as i am getting Error 51 .

Please explain if i need to create more than one line item how do i post the idoc .do i need to copy E1F1seg and create it using code (program).

for the current existing file does not have a reconcialliatry entry given in the idoc file .Please let me know on how to post this idoc using bapi or what is the way .E.g

E1FIKPF : FI Document Header (BKPF)

BUKRS : Name of global company code

GJAHR : Fiscal Year

BLART : Document Type - SA

BLDAT : Document Date in Document

BUDAT : Posting Date in the Document

MONAT : Fiscal Period - 05

TCODE : Transaction Code - FB01

WAERS : Currency Key

HWAER : Local Currency

GLVOR : Business Transaction - RFBU

E1FISEG : FI Document Item (BSEG) -1

BUZEI : Number of Line Item Within Accounting Document

BSCHL : Posting Key - 40

DMBTR : Amount in Local Currency

KOSTL : Cost Center

HKONT : General Ledger Account

WERKS : Site

E1FISEG : FI Document Item (BSEG) -2

BUZEI : Number of Line Item Within Accounting Document

BSCHL : Posting Key - 50

DMBTR : Amount in Local Currency

HKONT : General Ledger Account

WERKS : Site

in th above given example the line number one is provided by the xi system but the line item two with posting key 50 is not given in idoc file