Put ham on a rack in a roasting pan. Bake at 325F 90-120 minutes until done (130-140F). Brush with sauce during final 30 minutes.
Meanwhile, make sauce. Drain cherry liquid into a sauce pan. Stir in Madeira, sugar cornstarch and lemon juice. Cook over medium heat, stirring until sauce boils and thickens slightly. Boil 1 minute. Remove from heat and brush on ham during final 30 minutes in oven. Into the remaining sauce, add the canned cherries. Reheat. Serve with ham.