See the note at the end of the post before implementing this
Normally when you pass an optical drive through from the hyper-v server to the guest OS in a VM it can act as a read only device, even if it has writing capabilities. This is a limitation of Hyper-V.
However this can be worked around using iSCSI. Microsoft now make available their own iSCSI target software, but unless I’m mistaken that cannot share optical drives. Alcohol 52% Free Edition contains the ability to setup an iSCSI target device which you can then connect to from Windows 7 and will handle optical drives.
Install Alcohol 52% on the host OS, ignoring all the crapware and reboot as required. Then start the application and look down to the bottom towards the list of drives. Right click on the drive you wish to share and click sharing;
Then highlight the drive and click the new share button.
Give the share a name and highlight “share read” and “share write” then click ok
Back on the sharing window go to the options tab, enter a username and password and make sure the service is started and the startup type is automatic, this will ensure it still runs after a reboot.
Finally click ok and this completes the section on the host OS.
On the guest OS under Administrative Tools start the iSCSI initiator. Under the discovery tab click discover portal and enter the IP address of the host OS, leaving the port the same and click ok.
Then head back to the targets tab and click refresh. The iSCSI device setup should show, highlight it and click connect. Then on the next window click ok, leaving the details the same.
Finally the iSCSI device should show connected and if you check your connected drives you should see the device listed in My Computer.
Note: I salvaged this from a very old version of my blog, I know it applies to Hyper-V in Windows Server 2008 R2, but I’ve not tested this on any versions of Server 2012. This will work if you’re in a pinch and need it, but I couldn’t really suggest this for use in a production environment