Add new line/item to queue invoice.
If billondate = 0 – item will be added to the nearest invoice related to the given account (id).
If billondate = 1 – item will be scheduled for invoicing on a specific date (billdate).
On that day, cron will generate a new invoice or merge the item with the invoice created for the client.
GET /admin/api.php?api_id=API_ID&api_key=API_KEY&call=addInvoiceQueueItem&client_id=CLIENT_ID&queueitem%5Bdescription%5D=QUEUEITEM%5BDESCRIPTION%5D&queueitem%5Bamount%5D=QUEUEITEM%5BAMOUNT%5D&queueitem%5Bqty%5D=QUEUEITEM%5BQTY%5D&queueitem%5Btaxed%5D=QUEUEITEM%5BTAXED%5D&queueitem%5Bnote%5D=QUEUEITEM%5BNOTE%5D