Party,Business System & EDISeparator in B2B Scenarios

Hi Experts,

Started with my developments in ANSI X12 EDI Transactions.

There are few doubts mentioned below -

OUTBOUND

(Paty? or no Party)|ECC Business System --> PI --> Party|Business Component

We will have a party for the Landscape of our client. But, when I am giving the party with the business system, I am unable to trigger the IDoc from ECC system. Getting the below error -

So, do we require a party or not? If yes, do we need to do some settings in ECC?

INBOUND

Business Component -->PI -->(Paty? or no Party)|(EDISeperator Common)Business Component(Dummy Flow, for all the inbound interface)

(Paty? or no Party)|(EDISeperator Common)Business Component -->PI --> ECC Business System

In this,

1) Do we need a business system or business component for EDISeparater adapter. Which is preferable and why?

2)Is party required or not? As flow will increase if we keep party.

Please suggest.

Thanks,
Nidhi