Can't use 3TB drive in Xserve drive caddy?

I am using a 2006 Intel Xserve (10.6.8) at home for storing lots of multimedia. My 2 TB user drive, which is inside of one of the Xserve's drive caddies is nearly full. I purchased a $157 3 TB Seagate Barracuda (Model No. ST3000DM001) from Amazon and put it inside the caddy. It is not being recognized at all.

Looking around for solutions I am getting a hint that trying to restrict the data rate to 1.5 GB/s might help, which is documented for some of Seagate's older SATA drives, where one puts a 2-mm jumper clip on a header next to the SATA connector. This 3 TB model has the same header, but the manual only speaks of data rate autonegotiation. I'll be able to try out the drive with the jumper clip in place tonight and will report back.

Curiously, in my Thermaltake USB-2 interface (toaster style), Disk Utility shows the drive as "801.57 GB Generic External Media," which is being discussed in a Leopard Server discussion thread. Last I saw, there was no good explanation for this symptom.

If anyone has any suggestion on how to use a 3 TB drive in my Xserve, I would be most grateful. Perhaps it might have to be another manufacturer's drive, or maybe the 2006 Xserves don't support anything bigger than 2 TB. If you have evidence that your newer-model Xserve can do it, I'd be interested in that also.