First I'd like to apologise if my question has already been answered elsewhere - I've searched and not been able to find a solution as yet.

Here's my setup:

Gigabyte GA-Z77X-UD5H Wif Mobo
Intel Core i7 3770K 3.5GHz
3 x Seagate 3TB Barracuda Hard Drive - 3.5" SATA-III - 7200RPM 64MB Cache

I've enabled RAID in the BIOS on the Mobo and installed Ubuntu Server 12.04 LTS. During install the Fake RAID was recognised and Ubuntu 12.04 LTS was installed to the array, however, it only recognised 1.6TB whereas it should have recognised around 5.7TB.

On further Googling and trawling through forums I read that MBR partitions only recognise upto 2TB and I need to use GPT partitions and would be better served by using Software RAID as opposed to the Fake RAID on the Mobo BIOS.

I've spent a good few hours trying to find relevant and correct information as to the best way to install Ubuntu Server 12.04 LTS with RAID 5 on GPT partitions. Some forums suggest using a live CD to boot into Gparted to configure the GPT partitions, but don't elaborate on how to do it

What I need is the following:
Howto setup the hard drives using GPT partitions
What sizes and partitions need to be created, bearing in mind they're 3TB hard drives
The correct steps needed to enable Software RAID 5

Many thanks in advance