holset turbo engine brake

[hookliftpete]

The isc in this pete has a holset turbo. I've driven other isc's with a holset turbo that also was the 'engine' brake. When I look in insite at my ecm, it appears that this is possible with my truck, but I don't have a switch on the dash. Is this something that may be able to be activated and switch installed? Perhaps it was not ordered from the factory?