I uploaded the debian-6.0.7-i386-netinst.iso to file catalog, and created the kvm1 task in kvm. The command line was as below: name="kvm1" cpu-count=1 memory=1024MiB disk-images=hda:kvm1.img kernel=""
kernel-cmdline="" initrd="" vnc-server-address=0.0.0.0
vnc-server-display=0 snapshot=no state=no-disk-image
Now the breakdown is shown as "no disk image"