Expensive when compared to an R200 server, yes, but not so much when talking about an R510/R710 fully loaded with drives :) Wish I had better news for you.  You could simply use them as 2TB drives - there is no harm in that (but to the wallet :)).
I have a Poweredge R200This has a Raid 6i Controller with firmware 6.22.03.00 (2008.8.6)If I attach two Hitachi 3TB drives it only shows about 2.2 TB. How to get the controller to see and use all space? Regards, Eef 
How to use 3TB Harddrive on R200?