Heat oven to 350°F. Grease 4 (8 1/2- x 4 1/2-inch) loaf pans. Sift together flour, sugar, baking powder and salt into mixing bowl; stir in nuts. Whisk together eggs, bananas, soymilk, oil and vanilla; pour into flour mixture all at once, stirring just until flour is moistened. Divide equally among loaf pans. Bake 1 hour or until toothpick inserted in center comes out clean. Cool on wire rack 10 minutes before removing from pan; cool completely before slicing.