In that case OF recognizes this key. Normaly MorphOS is able to recognize also all features, OF recognizes. Eject-key should be known by MOS for that reason. As I can see on my PB, this key seems to be known on a lower level then the rest of the keyboard, because it cannot be found in USB-Keyboard-Prefs to map.
So, again: Does it work in early-startup-menue? If it does'nt, I think, there is no way for a normal user to solve that......but that is a question only MOS-Team can answer.