We need 2 Linux console/cronjob compatible scripts :
Script 1.) Import open orders into a PostgreSQL table via Amazon MWS (Marketplace Web Service). You need to check for dublettes so we do not get double entries in the database.
Script 2.) Check the same SQL table (where you imported before) for "shipped"-flag and export/report the shipment's tracking number (also in the same table) via Amazon MWS to Amazon. Then set (in the same table) a flag "reported" (and check for that flag in the next run so we don't report twice for the same shipment).