Logitech Cordless Desktop S510

[kdvgent]

I bought a Logitech Cordless Desktop S510 set (actually a S510 cordless keyboard and an LX5 cordless mouse)

In GNOME -> Desktop -> Preferences -> Keyboard -> Layout, which Logitech keyboard do I indicate to have the maximum of special keys available for configuration under Keyboard Shortcuts?

How do I add definition for special keys not defined under the "Keyboard Shortcuts" option?

Thanks in advance for helping