I currently run two XenServers with a few VMs.
My environment is mostly Windows and I'd prefer to backup the whole VMs to Windows backup machines.
follow the The backup python script has a configuration file with the backup to location. If you mount the windows share (with mount.cifs), you can use the backup script.
You can mount the windows share with something like:
mount.cifs //IP or Windows Server Name/sharename /backupmountpoint/ -o user=username password=password domain=Domain