Been a while since I did this, and I'm typing this from the manual and not double-checking on the bike.
Here goes... From the Main Menu, highlight Setup/Info and press ENT (on the right fairing panel).
Next, highlight Setup/Ceremony and press ENT.
Now, highlight Special and press ENT.
Then, highlight Detail and press ENT.
This should bring up the "Rename" keyboard. Here you can type in (up to) 17 characters (including spaces) to appear beneath the "Hello!" that comes up when you turn the key on. After typing, highlight OK and press ENT.
This should take you back to the "Opening/Ending Ceremony" screen, where you can highlight Done and press ENT.
If you've done it right, whenever you start the Navigation System, you will see a two-screen sequence: the Goldwing logo followed by a second screen that says "Hello!" with the text you entered. And when you exit the system, you will see a screen that says: "See you!" followed by the text you entered.
'08 Pearl White Navi