[libvirt-users] missing backend for pool type 5 (iscsi)

Hi, I try to define an iscsi pool with virsh but I always get the following error : error :internal error: missing backend for pool type 5 (iscsi) And yet libvirt was compiled with iscsi support : configure: Storage Drivers configure: configure: Dir: yes configure: FS: yes configure: NetFS: yes configure: LVM: yes configure: iSCSI: yes configure: SCSI: yes configure: mpath: yes configure: Disk: yes configure: RBD: no configure: Sheepdog: no configure: Gluster: no configure: ZFS: no And virsh report that iscsi is supported : virsh -V Virsh command line tool of libvirt 1.2.11 See web site at http://libvirt.org/ Compiled with support for: Hyperviseurs : QEMU/KVM LXC UML OpenVZ VMWare VirtualBox ESX Test Réseau : Remote Network Bridging Interface udev Nwfilter VirtualPort Stockage : Dir Disk Filesystem SCSI Multipath iSCSI LVM Divers : Daemon Nodedev Secrets Debug Readline Modular Any idea what's going on ? thanks for your help