Agent for Hyper-V does not back up virtual machines with pass-through disks and you cannot select them for backup under Virtual machines. If you include a group containing a virtual machine with a pass-through disk in a backup plan, this machine will be automatically excluded.
The reason is that the Microsoft Software Shadow Copy provider cannot take snapshots of pass-through disks and provide them to Agent for Hyper-V via VSS.
To back up a virtual machine with a pass-through disk, install Agent for Windows or Agent for Linux in the guest operating system. An Acronis Backup & Recovery 11 Virtual Edition license assigned to the host enables you to install agents in an unlimited number of the guest systems.
For more information about how to install the agent, see the installation documentation.
After you install the agent and add the machine to the management server, the machine appears under Machines with agents in the All machines with agents group. When creating a backup plan, select the machine here rather than under Virtual machines. Or you can connect the console to the machine directly as to a physical machine.