When I called, Nikki had me fill out the Online Reservatiion Form , and she emailed me all of the information (invoice, registration form, waiver) as .pdf files. I just had to call her with a credit card number.
In the comment section of the reservation form, I just put that we were part of Xterra Owners Group.

Need a current head count, so post up how many in your party.
My wife and I, so "2"