Preheat oven to 350 degrees. In a large mixing bowl, combine flour, wheat germ, sugar, cinnamon, baking powder, baking soda, and salt; set aside. In a medium size mixing bowl, combine soy milk, oil, vanilla, and mashed banana. Mix wet ingredients into dry mixture until thoroughly combined; batter will be thick. Stir in 1/2 cup nuts. Spray muffin tins with non-stick cooking spray. Fill muffin cups about 3/4 full. Sprinkle remaining walnuts on top of each muffin. Bake for 15 minutes, or until a toothpick inserted comes out clean. Cool for 10 minutes in the pan; transfer to a cooling rack.