We're on v2006, so I don't know if anything's changed in your version in relation to the invoicing XML.
In ours, when you close a load, the information gets transferred to the output tables. E.g. for the carton_hdr table, there's an outpt_carton_hdr corresponding table. This is true also for carton_dtl, pkt_hdr, pkt_dtl, outbd_stop, and outbd_load. From there, there's a Manhattan program called PkGenInvoicingFiles that needs to run to pick up the information in these output tables. This is the program that generates the XML file. In our environment, we have this program set to run every 10 minutes. Once the XML file is generated, you'd need a separate program to process it in your host system.