Intel Matrix Storage and 3TB?

Here's what I've got:

Intel Xeon CPU, E5620@2.40GHz

Installed memory 6GB

System type: 64-bit OS

Intel Matrix Storage Manager option ROM v8.5.2.1002 ICH10R/DO wRAID5

2 Seagate Barracudas, 3TB 64MB cache (STBD3000100)

The problem is that when I try to set up a RAID1 array, the setup program says that the drives are only 750GB.  But if I hit F2 before the machine boots, the computer recognizes them as 3TB drives.  I'm having some trouble with Windows recognizing them as over 2.25GB drives, and I know the Intel Matrix RAIDs can't recognize drives over 2TB.   But why is the raid not recognizing them as at least 2TB drives?  What can I do to fix this?  Switch down to 2TB drives?

Thanks in advance!