Somehow I managed to miss this reply for a month. I feel rather dumb now.
Anyway, here are a pair of screenshots
From an XP machine, under the Network listing:
From a Vista machine, under the same listing:
The Vista machines are running Vista Enterprise, with a standard 'default' install from a Microsoft CD (ie, it's not a vendor installation). The install was done 'clean', with a complete reformat beforehand. Is there an easy way to set IPEnabled=true from the command line or a startup script?