We were on the PG in December 2005 and the "onboard" booking process described by jbittle and JillM worked for us.
We were already booked on MUSH at the time. When we returned from the PG, B&K was able to apply an onboard booking discount toward our MUSH cruise. It worked beautifully! We did not even need to send in the form that was given to us on the ship.
It does work.
Dena
