Corned Beef and Cabbage

4 1/2 pound corned beef brisket
2 medium onions, quartered
2 cups water
1 head cabbage cut in small wedges
3 tablespoon vinegar
3 tablespoon sugar
1/2 teaspoon pepper 

Combine ingredients in removable liner with cabbage on top. Place liner in base. Cover and cook on low 10-12 hours or on high 6-7 hours.