Proxmox install not recognizing mirror drives as the same

Hi,

I am trying to install Proxmox 3.4 for our corporate server. I have two SATA hard drives installed - both WDC WD7501AALS-0 at 698GB.

The Installation recognizes both disks as /sda and /sdb, but when I try to install Proxmox as a ZFS RAID1, I get an error message:

Warning: mirrored disks must have the same size
Please fix ZFS setup first.

...and I can't proceed. How can I get this to work?

Thanks,

-PC