Hello Paolo,
for the support of volumes greater than 2 TB you will need an Intel RAID ROM v10.6.0.1091 or higher within your mainboard BIOS.
If the PC or mainboard manufacturer doesn't offer a BIOS with an appropriate Intel RAID ROM version, you probably have to update it yourself.
Especially for users like you I have written a guide about how to do it. You can find it here:
Good luck!
Fernando
