troubles with Seagate (EMC2) disk

[Riccardo Veraldi]

Hello,
I have a Seagate ST350000 CLAR500 disk.

it is attached to my Sun Blade 1000 running FreeBSD 9.1

I need to label it, create partition and move te root /usr/ var and swap 
from the main boot disk which has corrupted blocks.

so this disk will become my boot disk.

the problem is that I cannot partition it or even access it in anyway

dd: /dev/da6: Invalid argument
1+0 records in
0+0 records out
0 bytes transferred in 0.000700 secs (0 bytes/sec)

this is the disk information:

da6 at isp0 bus 0 scbus2 target 1 lun 0
da6: <SEAGATE ST350000 CLAR500 FDBD> Fixed Direct Access SCSI-3 device
da6: 100.000MB/s transfers WWNN 0x2000001862133c8d WWPN 
0x2100001862133c8d PortID 0xe4
da6: Command Queueing enabled
da6: 476940MB (961745856 520 byte sectors: 255H 63S/T 59865C)

the problem is that disk byte sectors are 520 and not 512

is there a way to reformat it to 512 byte sectors ?

is there a way to make it usable ?

the SCSI III disk has a FC - AL interface (Internal Sun Blade 1000 Caddy).

thank you

Rick