Hi Hammer,
If it's like the PA800, you can certainly save a new performance (song?) in a custom songbook (name the list whatever). Not sure if the songbook is the same.
If it is, you just have to make your changes and then start with the edit 1 page. It will walk you through the parameters. Then go to edit 2 page to save it to a custom location.
MAKE SURE THE ENABLE EDIT IS MARKED UNDER THE DROPDOWN MENU or else you'll be scratching your heads for hours like I did
Next, hit songbook and you'll see your new title there.
Hightlight it and hit 'send to list'
Then go back to your edit list page and hightlight that song and hit 'save'
Now you must make sure the custom list is updated by saving the changes, in effect a revised custom list.
When I wanted to edit that song, I just went back to edit 1 & 2 screens and named the song version 2, etc. That way you can erase the previous versions.
I believe every song you do that way will remain in your master songbook (annoying to me), but you can always redo the music resources and I believe your custom list will still be there (but not 100% certain).
It is a bit strange, but easy once you figure it out. In fact, I liked it a lot.
Hope this helps and good luck.
zuki