I have never done it on a steering wheel with an airbag but I believe the airbag is held in place by two screws that are accessible on the back of the steering wheel. Before you remove it I would suggest taking the positive terminal off of your battery and waiting a few minutes so there is no charge in the system. Once the airbag is off there should be one bolt holding the steering wheel down.

If anyone wants to jump in feel free. I have removed a non-SRS steering wheel before and I am not 100% sure if what I said covers everything.