Identifier? Mapping for File --> PO --> ERP (ABAP Proxy) Scenario

[JaySchwendemann]

Dear all,

Situation

I have the following scenario: Party_A (FTPS) --> PI --> ERP (ABAP Proxy)

Goal

I would like to get not the party name "Party_A" into ERP but some alternative Identifier (at best the customer number in KUNNR format 0123456789). I would then use ABAP Proxy protocol (if_wsprotocol_xi_header( ... ) ) to ideally get the customer number as dedicated identifier entry.

What I already tried

• Party_A Identifiers List

• Added Entry
  • Agency = <Receiver ERP Business System>
  • Schema = ALE#KU#AG
  • Value = 0123456789
• Added Entry (tried to "misuse" DUNS number for a customer number - used another number for clarity here)
  • Agency = 016
  • Schema = DUNS
  • Value = 9876543210

Sender Communication Channel (inline to iFlow, not a referenced channel)

• Identifiers Tab filled in any combination of the above entries to Party_A

Receiver Communication Channel (this is a refrenced channel)

• Header Mapping

• When I put in a valid combination of identifiers from above, it will result in Party_A / http://sap.com/xi/XI / XIParty being transfered to ERP.
• When I put in a non valid combination, e.g. Party = ACME, that value (ACME) will be transfered to ERP.

Identifiers tab

• filled in any combination of agency / schema ot the indentifiers list of Party_A

Where I struggle

It seems I do not get the concept (in full) of Identifiers or Header Mapping in this area. This is kinda trial and error. Documentation does not particularly help either. Community (SDN) content is scarse

My questions

1. Is using Identifiers in an Party to Business System scenario even possible / supported?
2. Would I need header mapping in my scenario? If so I currently could only make this work to map from say 9876543210 to Party_A, not the other way around
3. Where do I need to fill in the Identifiers tab. In the sender communication channel or the receiver communication channel or both?
4. Why is there both a "Sender" and "Receiver" section in the communication channel provided the channel can only be either a sender communication channel or a receiver communication channel, but not both

Many thanks and kind regards

Jens