Hi:
I own a PA 800 since November 2006 besides my Tyros2, and Yes, the Registration Set up or way on calling them is Totally diferent.
In the Korg PA series, the Family sound Buttons, are also the registrations, just have to look (in the middle Right side, torward the right end, look for a button "PERFORMANCE" = Registrations, when this is activated, the "Piano" Button becames the First Bank of 8 in that page, in the bottom of the screen you will see "Folder" Pages, Each Page has 8 registrations that you can make your own and replace them too.
All teh Keyboards will have a Learning Curve, when you get the hang of it, it becames easy.
I hope I did answer your question.
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mdorantes