cropduster,
I figured out how to mount it. You'll have to mount it manually from the command line. You'll have to first figure out which device your superdrive is under the /dev directory.
First put in a DVD that is actually mountable into the superdrive. Once it's mounted, go to terminal and type the df command and it'll show you which /dev/device it is. For me, it's /dev/disk2. Eject the DVD in the superdrive.
Now, put in the DVD that is not mountable (because it's missing a label).
Open up terminal, and type:
sudo mount_cd9660 /dev/disk2 /Volumes/CD
If the directory /Volumes/CD doesn't create, you have to create it first.
I think this was a minor oversight by the programmers. It should most likely be fixed in the next update/patch.