Unable to mount disk from ReadyNas NV+

Hi

I've read the support and forums to try get data back from a ReadyNAS NV+ with RAIDar 3.x(?) but am running into mount problems.

ReadyNAV NV+ symptoms: very slow to boot, came up with a sync message. suspect one of the drives is failing. On last reboot it took over 30 hours before I gave up.

Config: 4 disks in 2 RAID1 volumes.

So I've pulled out the first drive and connected via a USB dock to my Ubuntu 10.4 server, and did the following:

$ sudo mdadm --create /dev/md2 -v -f -l 1 -n 2 /dev/sdf3 missing
mdadm: /dev/sdf3 appears to be part of a raid array:
    level=raid1 devices=2 ctime=Wed Aug  1 23:45:28 2007
mdadm: size set to 485804992K
Continue creating array? y
mdadm: array /dev/md2 started.

$ sudo pvscan
  PV /dev/md2   VG c   lvm1 [463.25 GiB / 0    free]
  Total: 1 [463.25 GiB] / in use: 1 [463.25 GiB] / in no VG: 0 [0   ]

$ sudo vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "c" using metadata type lvm1

$ sudo vgchange -ay
  device-mapper: reload ioctl failed: No such device or address
  2 logical volume(s) in volume group "c" now active

If I try and mount it with mount, fuseext2 or ext2fuse I get mount errors:

$ sudo mount -o -ro,user -t ext2 /dev/c/c /media/nas
mount: wrong fs type, bad option, bad superblock on /dev/mapper/c-c,
       missing codepage or helper program, or other error
       (could this be the IDE device where you in fact use
       ide-scsi so that sr0 or sda or so is needed?)
       In some cases useful info is found in syslog - try
       dmesg | tail  or so  

syslog

Nov 17 17:42:12 kernel: [ 1320.006146] EXT2-fs: unable to read superblock  

and with fuseext2

~$ sudo fuseext2 /dev/c/c /media/nas -o ro
Open_ext2 Error:22  

even debugfs doesn't work

$ sudo debugfs -c /dev/c/c
debugfs 1.41.11 (14-Mar-2010)
/dev/c/c: Invalid argument while opening filesystem  

and fsck fails too

 $sudo fsck -n /dev/c/c
fsck from util-linux-ng 2.17.2
e2fsck 1.41.11 (14-Mar-2010)
fsck.ext2: Invalid argument while trying to open /dev/mapper/c-c

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>

is this disk really screwed?

Edit: on disk 2 I get the same errors, and on disks 3 and 4 (the second RAID1) pvscan fails with

$ sudo pvscan
  Snapshot and origin LVs must differ.
  Couldn't add snapshot.
  Snapshot and origin LVs must differ.
  Couldn't add snapshot.
  No matching physical volumes found   

Am I missing something? The last backup was two weeks ago so I want to get the data from that point on..