require billing address

Is there a way to require a billing address during checkout?

I have had too many orders approved with a blank billing address. I am using Authorize.net AIM and have AVS setup so that it should reject transactions with no billing address, however some banks return a P code instead of B code for that and there is no way to tell Authorize.net to reject those.

Is there a way to set up zencart so that the billing address is required when checking out?

Thanks!
Melissa

I am also in this functionality... anyone with ideas on this?