Here is a link.
GM Integrated Brake Controller - Chevy and GMC Duramax Diesel Forum
Personally, if I was to go with a disc brake system, I would use a good aftermarket brake controller instead of wiring a magnet inline to "fool" the Integrated unit. Also, many post suggest that there is a 2-3 second delay for the disk brakes to engage with the OEM controller. Not a good thing.
2005 Bigfoot 1500C8.2 Truck Camper; MANY mods, to many to list
2007 Chevy 2500 Duramax Std Bed Ext Cab