Hi - I do. I think!
The way I did it and it's working so far is just go to the planning tools and select RSVP....the "general RSVP cards". This will give you the personal code for each guest. Once that's done - you can see the list of guests along with their code under the planning tools, invitiations. I didn't use the RSVP card that was provided with the site, rather just wrote the code for each guest on my RSVP card.