We did use the checkout wizard. The problem is that it collects shipping and billing info that are ALSO taken care of by the Authorize.net page that you go to when you hit checkout. That's when we went to Help and found the section about inserting a remote checkout form... is there a way to use the wizard but NOT have them have to fill out shipping and billing info twice?
Also when we tested it, this message showed up:
https://www.dropbox.com/s/2oudukbqoa6kjkp/Screenshot%202015-01-29%2009.07.39.png?dl=0