Public Access for supplier registration using CAS (Central Authentication Service) software

We have begun our project to implement Supplier Onboarding and Bidder Registration.  I have completed the setup including the steps required for public access; however, our CAS software requires me to enter a UserID and password.  I was wondering if any of you could give me some pointers about how to design public access that could bypass the CAS authentication.  I want to provide the correct instructions to our engineering team.  For example, do I request the CAS bypass to be URL based or something else?

Thanks,

Mike Staton