Place the beef in the freezer for an hour or so until it is firm but not frozen. Slice it into thin strips with the grain and place them in a large flat-bottomed glass dish. Whisk together all the marinade ingredients, pour it over the meat, and toss to coat evenly. Refrigerate for 4-6 hours.
Meanwhile, light a few coals in the bottom of the Broil King Keg, and control the airflow vents at the top and bottom to maintain a temperature of about 160-170°F. (Both will be open to about 1 1/2.) Set the diffuser pan over the coals, but do not fill with any liquid. Place the strips of meat on the grids so that there is enough space between them for the warm air to circulate. Check every few hours to ensure that the temperature is maintained, and move the strips around if necessary for even cooking. Total cooking/smoking time will be about 8-10 hours.
Beef jerky will keep for up to a week in the refrigerator.