Add Field to SAP RFC Table Using .NET Connector 3.0

Note that it is not possible to append table’s column as fields are already defined. You can only enter a row to the table and populate fields to that row. Below code should work −

IRfcTable ITEMDATATable = BapiIncomingInvoiceGetDetail.GetTable("ITEMDATA");
ITEMDATATable.Append();
ITEMDATATable.SetValue("SKU_ATM",myItemData.SKU_AMT);