New Sort Key - KNUMA

Hi

In Std sorting for line items

IMG->Financial Accounting>General ledger>Line Items->Display Line Items ->Determine Standard Sorting for Line Items

Is there any Option to add new field, apart from the fields listed. I want to add field KNUMA here. (KOMV-KNUMA).

Kindly let me know how to add this new field, so that i can select this field and create new sort key.