I would like to export Virtuemart orders. Most of it works fine, but I need the delivery date (or invoice date). If I select the field delivery_date the output is the string "same as invoice date" and not a date. A field invoice_date is obviously not available for export. I tried to use modified_by as a workaround, but that only works for orders where the status isn't changed later to e.g. refunded.
Any ideas how the invoice date could be exported?