Hi Anton,
Sorin is right: For each graphic template, you can choose from ANSI, ISO, and JIS:
For your internal keyboard, you may choose Powerbook USB internal or Aluminium Wireless, for the external one, you may choose Aluminium Apple – but always with ISO showing in the drop-down menu!
Please note that the display is just an aid during editing; the correct functioning of your keyboard layout doesn’t depend on whether you can find an exact match for your keyboard in the list.
On the other hand, choosing ANSI or ISO makes a difference for the key next to the digit 1, as you have noticed, so it’s important to get that right.