Mac OSX Lion - Windows 8 bootcamp

I'm trying to install Windows 8 on my Mac (10.7.5) but I'm running into some big issues. First I'll explain what I already did.

1. I created a partition with the Boot camp assistant (151 GB)


2. I installed a ISO on my external hard drive.


3. I rebooted my Mac holding the option key so I could choose a start drive disk


4. I selected EFI BOOT


5. I entered my serial number and continued.

And here does the trouble begins:

6. Now a see a list of drivers and my partition but I can't select my Drive 0 Partition 4: Bootcamp

The error I get:

"Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed to GPT disks.

Windows cannot be installed to this hard disk space. Windows must be installed to a partition formatted as NTFS.

Windows cannot be installed to this disk. This computer's hardware may not support booting to this disk. Ensure that the disk's controller is enabled in the computer's BIOS menu"

I already tried to run this command(s)

diskpart
select disk 0                      (assuming 0 is the disk where you created the bootcamp partition)
select partition 4                 (assuming 4 is your bootcamp partition)
format fs=NTFS label="Windows 8"   (I didn’t use QUICK)
exit
exit

Note: Drive 1 is my external hard disk.