EXPVZ & IEVER field is blank in Foreign trade Tab, for return invoice

Hi,

EXPVZ & IEVER field is blank in Foreign trade/Customs Tab, for return invoice.

It is a domestic sale scenario, and in VFX3 -Invoices is not released for Accounting, due to the incomplete fields.

In this case how do I default data to EXPVZ & IEVER fields within invoice, so that the accounting document gets cleared?

Regards,

Shilpa