ReadyNas NV +2 - LOCKED Harddrive

I currently have a Readynas NV +2
I recently had in the NAS 4x Seagate 2tb hard-drives [ST2000VX002] but I have recently replaced them with 3tb drives.

The Nas is running fine with the 3tb harddrives and X-RAID'd, however the removed 2tb drives are all locked.

I have tried to format them in the desktop pc I would like to use them in but it will not initialise and I believe they are locked. I have read various forum postings and tried the suggestions for example the following link, but I still cant unlock the hard drive

http://www.readynas.com/forum/viewtopic.php?f=66&t=59488&p=334292&hilit=locked+hard+drive#p334292

I have tried all of the following with no success
Put all the drives back in the NAS and did a factory reset and then an erase - HDD still locked
Put all the drives back in and did a JBOD - HDD still locked
Put one locked drive in and performed a factory reset and then powered down - HDD still locked
Put one locked drive in and performed a factory reset and erase - HDD still locked

What can I do to recover my 2 tb hard drives rather then send it to the scrap heap...HELP!!!!