I called them myself and said the supp holder had no SSN then gave the passport number. I believe live chat from your account might work as well now. Once supp card holder got an account, he or she can use her own live chat to activate.
I'm not quite sure but I think I got them to create an account as well. Back at those days, each supp card needed its own account even when they were in the same name but these days one account can handle multiple supp cards.
Also waiting to hear some updated info on this.
