This does not happen often, but sometimes the driver caches do not get purged and the new SATA driver does not get loaded correctly from ROM.
1) Delete and empty trash for the following file and two directories:
/System/Library/Extensions.mkext (a file)
/System/Library/Caches/com.apple.kernelcaches (a directory)
/System/Library/Caches/com.apple.romextensions (a directory)
Under Mac OS X 10.3 and 10.4, a volume greater than 2TB will show as a 2TB volume due to a limitation in Apple's ATA layer (just above the driver). Sonnet plans to provide a 10.4 fix in the next driver release. Under Mac OS X 10.5 and 10.6, the full capacity of the RAID volume is available.