I'm using the simple checkout gateway and am wondering if there is a way to modify the payment form. I have the form options checked for a "customer ID" field. But I would prefer it if that field read "Customer Account Number". I know there isn't an option to change that field, but is there a way to add a customized field to the payment form?
Not from what I've read. You could theoretically update to DPM, which allows you to set up the form on your site but submit to Authorize.net, so the form can be much more customized than if you just go straight to Authorize.net.