Weigh or lightly spoon flours into dry measuring cups; level with a knife.
Combine flours, cornmeal, raisins, baking soda, and salt in a large bowl; stir with a whisk.
Combine buttermilk, molasses, butter, and rind.
Add to dry ingredients; stir just until moistened. Divide batter evenly between 2 (8-inch) loaf pans coated with cooking spray. Tightly cover each pan with foil.
Place pans in a 13 x 9inch baking pan.
Add boiling water to a depth of 1 inch. Cover larger pan with foil.
Bake at 350 for 1 hour and 10 minutes or until a knife inserted in center comes out clean. (Top of bread will feel slightly sticky.)
Remove pans from water. Cool 10 minutes on a wire rack.