In a mixing bowl, cream margarine and sugar. Beat in egg substitute and pumpkin. Combine the dry ingredients; add to creamed mixture alternately with buttermilk. Stir in oats and dates. Pour into an 8x4x2" loaf pan coated with nonstick cooking spray. Bake at 350 degrees for 75 minutes or until a wooden toothpick inserted near the center comes out clean. Cool in pan 10 minutes; remove to a wire rack to cool.