The reference line item number(field REFDOCLN) is initial in Special Purpose Ledger (FI-SL) documents created from SD billing documents for the following reasons:
- Generally in accounting documents created from SD billing the reference line item number is not the line item number from Financial Accounting, but the line item number from the SD billing document(field POSNR_SD in the accounting interface).
Therefore the reference line item number is always initial in line items not directly referring to a certain SD line item number, e.g. in a customer item, but usually it´s noninitial in a revenue/expense item or tax item. However that in your scenario REFDOCLN remains initial even in an FI-SL item created from a revenue/expense item directly referring to an SD billing item in the accounting interface.
- In your system you´ve activated document splitting in General Ledger Accounting (New). The summarization of SD tax items according to note 1538860 is active in your system, because you haven´t marked the checkbox "Do not summarize SD tax items" in the customizing of document splitting.
- For this summarization of SD tax items, document splitting in New G/L clears the content of the SD line item number field POSNR_SD in the split items for tax items according to note 1538860 as well as for other (e.g. revenue/expense) items according to note 1894525, which is already included in the Support Package level of your system.
- In system with both Special Purpose Ledgers without document splitting and New G/L with active document splitting, the FI-SL document is created based on the result of document splitting in General Ledger Accounting.
However in this split document the SD line item number, from which the reference line item number is to be derived in FI-SL, has been cleared by the summarization of SD tax items in document splitting. Therefore the reference line item number isn´t filled in the FI-SL document.
So if you need the SD line item number (source field POSNR_SD) from an SD billing document to be transferred to the reference document number field REFDOCLN in an FI-SL document in a system with active document splitting in New G/L, you´ll have to suppress the summarization of SD tax items at document splitting by activating option "Do not summarize SD tax items" in New G/L document splitting customizing step "Assign Document Splitting Method".