This is basically the cornmeal equivalent of making your own self rising flour.
I have a cornbread recipe here and I have non-self rising corn bread. Do I do the same ratio of baking soda and salt to make it self rising?
yes. That is the basic different between self-rising cornmeal and regular cornmeal.
From Food.com: http://www.food.com/library/cornmeal-59
Self-rising cornmeal is a white or yellow cornmeal with leavening agents and salt added. Substitutions: 1 cup plain cornmeal + 1 1/2 tsp baking powder + 1/2 tsp salt = 1 cup self-rising cornmeal