The best way to do this is using two APIs. There is an API for the web store and an API Sage 100. The web store API requests the tracking number from Sage 100 via a JSON file, and Sage responds to the request with a JSON file containing the results, that then get presented to the user. We have done a lot of this work.
------------------------------
Doug Higgs
Midwest Commerce Solutions, Inc
(312) 315-0960
Chauffeur, Chef, and Personal Assistant to Sprinkles
------------------------------