This method returns a CSV document containing invoice items. The required fields are the username and password of the account.
The datefrom and dateto dates restrict the data to the specified date range.
A propid or roomid can be specified to restict the results to that property or room.
If the option "only with invoice number assigned" is set, only invoice items with an assigned invoice number are shown and the datefrom and dateto dates restrict the invoices shown by the invoice date.
Otherwise the date range specifies the date the invoice item was created.