First off you will need to register for a Manufacturer ID to be able to then generate your own Unique ID from it. They are free to register and details are available here:
http://tsp.esta.org/tsp/working_groups/CP/mfctrIDs.php
I'm not sure if there is an API for you to control the DMX Cat from your own application. Others here may be able to answer. Many of the OpenUSB DMX interfaces allow you to write your own code to control them though.