I tried tagging the project using the "Tag Repository" menu on the project web site. This appears to work except that when the packager wakes up, it doesn't find any change and doesn't generate the release file.
Here's the exact packager message:
Discovered git repository: wow/aboutis/mainline
Joining all threads
Updating git://git.wowace.com/wow/aboutis/mainline.git in /media/cf-repositories/packager/git-local-checkout/wow/aboutis/mainline...
Done with git://git.wowace.com/wow/aboutis/mainline.git
Finished joining all threads
Deciding to skip git repository: wow/aboutis/mainline, as not updated.
When I pull or fetch the change from the WoWAce repository, the tag is not there.
You're using a Git repository, which cannot be tagged via the web interface (I know, it shouldn't even be displayed...) - using commandline, navigate to your project on disk and type "git push --tags" to actually tag the remote repository. Most Git clients have options for pushing tags as well.