Preheat oven to 350 degrees. Mix grated potato, flour, raisins and baking powder. In a seperate bowl mix evaporated milk, coconut milk, sugar, vanilla, salt, sherry rum and butter. Pour milk mixture into potato mixture and beat until smooth. Pour into a greased 9 inch pan. Rest mixture for ½ hour. Bake at 350 degrees for about 1½ - 2 hours, until center is set. Serve hot or cold.