Preheat the oven to 375 degrees F (190 degrees C). Line muffin pans with paper liners, and spray the tops with cooking spray.
In a large bowl, mix together the margarine, 1 1/4 cups of sugar, and salt until smooth. Beat in the eggs one at a time until well blended. In a separate bowl, stir together the flour and baking powder. Spoon some of this mixture onto the blueberries, and toss to coat. This will keep them from sinking to the bottom. Stir the remaining flour mixture into the bowl with the eggs, alternating with the soy milk. Gently fold in the blueberries. Spoon the batter into the muffin cups, filling to the top. Sprinkle a little sugar over the tops of the muffins.
Bake for 25 minutes in the preheated oven, or until muffin tops are golden brown, and the tops spring back when pressed lightly. Cool for at least 10 minutes before removing from pan.