I was running into a problem earlier, and I'm not sure if it is a bug or not (depends on how it was intended), but when trying to mount an ISO image with spaces in the filename for creating a KVM machine everything proceeded as normal, however the CD-ROM drive was never created. I went back and tried to add it again under the hardware tab, and again I didn't get any error or anything, but the CD-ROM device was never created. I then renamed the ISO and tried again and it worked fine..