Ah, got it.

First, I merged the rc files. Second, I should have constructed the 
KConfigSkeleton like this:

    KConfigSkeleton *cfg = AudioCdSettings::self();

Third, in my .kcfg files, I had followed the tutorial an used Capitalised 
entry names; I eventually realised that the case had to match the widget 
name.

Ben, do you have any objection to merging the rc files as per this thread? The 
point is to make the audiocd kcm module available to kscd and kaudiocreator 
etc.

Thanks, Shaheed