Cook corned beef according to package directions. At the last hour of cooking, add the potatoes to the pot and continue to cook until the meat is very tender and begins to fall apart. When the meat and potatoes are done, remove them from the pot and reserve the liquid. Place on a serving platter and cover with foil. Add cabbage to the reserved pot liquid and simmer for 15 minutes or until cabbage wedges are soft, but not quite limp (to preserve wedge shape). Remove the cabbage wedges from the pot and add to the serving platter. Serve warm.