DSN - Service Entry Sheet in error (missing PACKNO and INTROW)

Hello Team,

during SES registration, we find an inconsistencly in WS for flow "ServiceEntrySheetRequest_Async_In" due to missing fields, so S4 is not able to perform SES creation.

here are the steps we did:

1) Creation of PO with Service Position --> OK

2) Supplier receive it, perform Confirmation --> OK

3) Supplier perform SES in AN subsequently --> OK from AN Supplier side, OK from CIG side, but then in S4 webservice goes in error with below message:

Service XXXX cannot be registered (Msg Id : SE Msg No : 147)

Further checking, we could find that Interface from AN is not sending PACKNO and INTROW value in payload, so the WS is not able to fulfill the SES creation.

When we try to perform a manual ML81N, we could see that above values are automatically picked by the Bapi, so this means that PO is correct but somehow the payload for the SES is incomplete or missing those info.

Could it be that those 2 fields are not passed in SES interface because, at beginning of the flow (PO creation with Service Position) are not present in payload itself, so info are not passed in AN from the beginning?

From S4 side we see that ESLL table is maintain correctly, so this confirm the hypotesis above.

Is then this issue due to missing configuration on S4 side? Do how hypotesis is correct? if so, how to solve then from the start?

Thanks!