vc-annotate and SCCS

I use vc (both the old at work and Ville's new version at home). I occasionally annotate files in our CVS repository ("who's to blame for that boneheaded mistake?" - usually me ;-), but we have a few files which are still in SCCS. As far as I know SCCS doesn't have any sort of annotate command. When I execute vc-annotate on an SCCS-managed file it responds File /x/y/z is not under version control That's almost certainly the wrong error message. I can check the file out, check it back in, etc.

This is the old vc (whatever comes with 21.5.28), not the new.