verify raid set grayed out

[polypus]

hi all,

machine:

Jan 2008 mac pro w/ Apple raid card, 4 x 500 GB Western Digital enterprise drives & 16GB RAM from OWC

problem:

from raid utility manual:

"To verify a RAID set:
1 Open RAID Utility.
2 Select the RAID set in the list on the left side of the window.
3 Click Verify RAID Set. "

but 'Verify RAID Set' button is grayed out if i select either my single
jbod or 3 disk raid 0 array. any idea why?

thanks for any tips,
_c