Preheat oven to 350°F. In a food processor, cream tofu, sweetener, oil, vanilla, egg replacer and banana. In a bowl, combine flour, baking powder, and baking soda. Add to food processor along with salt and process until creamy. Pulse in poppy seeds. Pour into an oiled 9x5x3-inch loaf pan. Bake for 30 to 35 minutes, or until toothpick inserted in center of bread comes out clean. Cool on a wire rack for 30 minutes before removing from pan. Yields 1 loaf.