Need help manually assigning a disk volume label

UNIX AIX
1

I've managed to bork a volume label on a disk that's shared out via GPFS. There has to be a fairly simple dd command to rewrite the blocks in question, but I can't seem to dig up the information necessary anywhere I look. Any help would be greatly appreciated!

 Fri Feb 28 15:20:26 EST 2014: mmcommon preunmount invoked.  File system: testfilesystem  Reason: SGPanic
  Fri Feb 28 15:20:45.803 2014: Command: mount testfilesystem 13303894
  Fri Feb 28 15:20:45.965 2014: GPFS: 6027-1502 Volume label of disk DISK1 is corrupt.
  Fri Feb 28 15:20:45.966 2014: GPFS: 6027-1501 Volume label of disk DISK1 is 00000000:00000000, should be 0A485897:5113C74B.
2

FYI, for anyone interested in this information at a later date :
"Issue the mmdelnsd command for each NSD in the cluster to remove the NSD volume ID written on sector 2."

its buried in one of the gpfs redbooks.