What does the setExternalID actually refer to?
We assumed this was referring the source (POS)'s Order ID/Invoice ID.
But based on some discussion earlier today and checking examples , it seems this should refer to "external payment id".
If this the case, how can we set the POS's source order/invoice ID in Sale Request?
The underlying transaction object seems to have:
java.lang.String getExternalPaymentId() java.lang.String getExternalReferenceId()