Navigate to the eBanking Setup page from search.

All relevant fields are under the BPAY Purchase tab:

  • BPAY file extension: This should be .bpb for NAB, .aba for CBA.
  • BPAY Single Debit: When ticked, a single balancing entry for bank will be created in the Payment Journal.  Otherwise, there will be separate bank entries for each journal line.