Heat oven to 190ºC . Cut margarine into flour, sugar, baking soda, baking powder and salt with pastry blender until mixture resembles fine crumbs. Stir in raisins and just enough buttermilk so dough leaves side of bowl. Turn dough onto lightly floured surface. Knead until smooth, 1 to 2 minutes. Shape into round loaf, about 17 cm in diameter. Place on greased cookie sheet.
Cut an X about 1 cm deep through loaf with floured knife. Bake until golden brown, 35 to 45 minutes. Brush with margarine or butter., softened, if desired. 1 loaf (12 servings); 125 calories per serving.