First thing you need to check if the problem is with passing the drive to XCP-ng VM, like @Biggen said, try lsblk inside xcp-ng VM (there is an option to go to shell in the installation menu if you haven't installed XCP-ng. If the XCP-ng VM only sees 1 device then it is a libvert/virt manager issue.

I'm not familiar with that particular script, so I can't help you debug further. Best option at this point is to blow away the VM and start over with a completely fresh install of Ubuntu.