There is a big difference between Corned Beef and plain Brisket. They both come from the same cut, but Corned beef is cured meat. It will remain pink no matter how long you cook it. The best way to cook corned beef is to boil it or braise it for 3-4 hrs. That’s what you’d cook on St. Patrice’s day with cabbage. You could start corned beef in a water smoker for the first hour of cooking, and then finish it in liquid.
Try the process again with plain (unprocessed) brisket. Cook it long and slow. I usually cook mine for 10-12 hours. Don’t forget the rub and the mop, they’re very important for moist and tasty brisket.
You can check the following web site for detail explanation of the process: http://www.smokering.net/
Better yet, get Steve’s book “How to Grill” and read all about it.