[libvirt-users] VMs XML difinitions can't be recognized after upgrading to libvirt 0.9.13

I used to run many VMs on my Ubuntu 10.04 box. However, after upgrading to Ubuntu 12.10 (and thus, libvirt 0.9.13), The VMs can't be recognized anymore. Nothing appears in the output of 'virsh list --all', nor in virt-manager. When I created a new VM based on a disk image of one of the not-recognized-any-more VMs, a new schema file has been auto-generated, and the new VM now is recognized. So, if this is caused by incompatibility with the old schemas, would the solution be to manually recreate all the VMs by importing their disk images to the newly created VMs, or is there a more intelligent approach? Thanks for your time. Marwan