Heat oven to 350. Grease bottom only of 8X4 inch loaf pan. In large bowl, beat sugar, margarine until light fluffy. Add butter, eggs; blend well. In small bowl, combine flour, nuts, dates, orange peel, baking powder, baking soda and salt; stir well. Add to buttermilk mixture; stir just until ingredients are moistened. Pour into greased pan.
Bake at 350 for 55 to 65 minutes or until took pick inserted in center comes out clean. Cool for 15 minutes; remove from pan. Cool completely. Wrap tightly and store in refrigerator.