I can confirm that it works just fine. I am using RAIDiator 4.1.8 [1.00a043]. I previously had 2 x 500GB drives. When one of them stopped working, I bought 2 new ST2000DM001 yesterday. I inserted the first drive (hot plugged). It took about 4 hours to initialise and approx. 2 hours to sync.
Once the first drive was synced, I removed the old 500GB and inserted the 2nd 2TB. Again it took similar time to initialise and sync. The space allocated was still 461GB. When I returned from work today, I switched the NAS off and back on. On the NAS browser page a message popped advising that first phase of volume expansion had started and the I should reboot the NAS to complete. Rebooted the NAS and within few minutes the volume had been expanded.
I know the question is about whether the drive is supported or not but thought it would be helpful to share the full experience for other users who maybe like me aren't too sure of what is supposed to happen.