Although there is detailed information about realmd.conf online, it should also be available as a man page: http://www.freedesktop.org/software/realmd/docs/guide-configuring.html
Fixed upstream.
This has been fixed in realmd-0.14 and later.
This is now live in stable after this update: https://admin.fedoraproject.org/updates/FEDORA-2013-7787/realmd-0.14.0-1.fc19