Update 3:
You could try this software: http://www.incentivespro.com/hyper-v-usb.html
It has a free trial.
Update 2:
According to this website:
Hyper-V doesn't allow the pass-through of a USB-attached device on a
host to a VM. This would break the desired abstraction of the VM from
the hardware, and therefore stop VM mobility. however this doesn't
mean there are no solutions.
This requires the use of third-party solutions that enable USB over
IP. The solutions work by having a physical server that has all the
USB devices connected to it and runs a service that enables the USB
devices to be accessed remotely over IP.
The VMs then run a piece of client software that connects to the USB
device over IP, and it looks to the VM like a local USB device. The
benefit to these types of solutions is the VM can still be moved
between hosts without losing connectivity to the USB device. There are
many solutions available; among them are two I have seen used by my
customers:
Silex SX-2000U2
Digi Anywhere USB
Update:
Looks like you're out of luck for the 10 Pro. MS page says:
The virtual machine must have Remote Desktop Services enabled and run
Windows Server 2012 R2 or Windows 8.1 as the guest operating system.
Answer:
Updated: May 20, 2015
Applies To: Windows Server 2012 R2
You can give a virtual machine access to a computer’s local resources,
like a removable USB flash drive, when you use Virtual Connection
Manager (VMConnect). To make this happen, turn on enhanced session
mode on the Hyper-V host, use VMConnect to connect to the virtual
machine, and before you connect, choose the local resource that you
want to use.
- Turn on enhanced session mode on Hyper-V host
If your Hyper-V host runs Windows 8 or Windows 8.1, you might not have
to go through the following steps to turn on enhanced session mode.
It's turn on by default. But if your host runs Windows Server 2012 or
Windows Server 2012 R2, you must turn on enhanced session mode to use
it. It is turned off by default for those operating systems.
To turn on enhanced session mode,
1) Connect to the computer that hosts the virtual machine.
2)
In Hyper-V Manager, select the host’s computer name.

3) Select Hyper-V settings

4) Under Server, select Enhanced session mode policy.

5) Select the Allow enhanced session mode check box.

6) Under User, select Enhanced session mode.

7) Select the Allow enhanced session mode check box.
8) Click OK
- Choose the local resource that you want to use
You can choose a local resource like a printer, the clipboard or a
local drive that’s on the computer that you’re using to connect to the
VM.
To select a local resource like a drive,
1) Open VMConnect.
2) Select the virtual machine that you want to connect to.
3) Click Show options.

4) Select Local resources

5) Click More.

6) Select the device that you want to use on the virtual machine and
click Ok.

7) Select Save my settings for future connections to this virtual
machine.

8) Click connect
Source: https://technet.microsoft.com/en-us/library/dn282274.aspx