1. Preheat oven to 350º F. Grease three 1-pound coffee cans. In large mixing bowl, combine flours, cornmeal, baking soda, salt, and raisins; mix well. Combine buttermilk, molasses, and melted shortening; add to dry ingredients mixing well.
2. Pour batter into greased cans filling 2/3 full; cover with foil. Place cans on rack in shallow pan. Place pan in oven. Pour boiling water around cans to depth of 2 1/2 inches.
3. Steam breads 3 hours until toothpick inserted in center comes out clean. Cool 15 minutes and remove from cans. Serve warm.