[ovirt-users] how to attach lvm device to VM ?

Hi, I have created LVM partition in host. I don't want that partition to act as storage domain in ovirt, but I want to attach that partition to VM. So I used virsh command to attach device to VM and it was successfully attached (block device as raw type). But when I tried to take snapshot of VM from Ovirt, it fail to get snapshot. I think it may be due to vdsm as it is not aware of newly attached lvm device. Can someone help me to know another way to attach device to VM in Ovirt? I tried with vdsClient but not got idea or command that will attach device to VM. Thanks, ~Rohit