Hyper-V Core Disk Size Limitation

We are running SBS 2011 virtualized on Hyper-V Core and have added 2x3TB USB3 external hard drives for backup (one for core, one for sbs) through a USB 3.0 controller card on a Dell PowerEdge T320 server.
Hyper-V recognizes the drives as the proper size but SBS 2011 sees the drive assigned to it as only 349GB.
When setting up the drive through Disk Management, an Initialize Disk window pops up. After clicking OK, another window pops up (Virtual Disk Manager) with the error “When accessing a new tape of multivolume partition, the current block size is incorrect”. After all is done, SBS only sees the drive as 349GB (see attached screen shots).

This is the first time I have tried to use 3TB drives. In the past, I have always used 1 or 2TB drives with no issue.

Is this a limitation or is there a work around?

Thanks!
Maurice Werner
Virtual-Disk-Manager.JPG
Initilize-Disk.JPG
DiskManagement.JPG