+=item po_number
+
+Purchase order number (normally not required).
+
+=item tax
+
+Tax amount (portion of amount field, not added to it).
+
+=item freight
+
+Freight amount (portion of amount field, not added to it).
+
+=item duty
+
+Duty amount (portion of amount field, not added to it).
+
+=item tax_exempt
+
+Tax exempt flag (i.e. TRUE, FALSE, T, F, YES, NO, Y, N, 1, 0).
+
+=item currency
+
+Currency, specified as an ISO 4217 three-letter code, such as USD, CAD, EUR,
+AUD, DKK, GBP, JPY, NZD, etc.
+
+=item partial_auth
+
+If you are prepared to handle partial authorizations
+(see L<partial_auth_amount()|/"partial_auth_amount()">
+ in L<TRANSACTION RESULT FIELDS|/"TRANSACTION RESULT FIELDS">),
+pass a true value in this field to enable them.
+
+=back
+
+=head3 CUSTOMER INFO FIELDS
+
+=over 4
+
+=item customer_id