I've found recently a Guide to Extend IDOCs ( https://blogs.sap.com/2019/08/25/extending-generated-function-module-based-idoc/ ) I've followed all the steps, but couldnt generate the new IDOC in BDFG.
I've append a structure in COD_S_SLS_ITEM_DATA, but that seems not enough (There is also a Segment called E101COD_S_SLS_ITEM_DATA) . After checking the FM COD_REPLICATE_SALES_ORDER in BDFG following message is shown "Incompatible change to complex data type or IDoc type <append structure name>.
Is there any Guide for extending IDOC COD_REPLICATE_SALES_ORDER (especially items)
Thanks in Advance and best regards