Formatting External SMT Raid Enclosure in OSX

I was unable to format an external enclosure using the disk utility in osx.
It would jsut error out.

However I found a command line to format the drive.

First do the following:
Open Terminal and run:

diskutil list

This tells you the location of the drives on your mac.
In my case i only have 1 internal drive and 1 external drive plugged in.
The external drive is disk1.

Then to format the drive run the following command in termainal:

diskutil eraseDisk "Journaled HFS+" desiredvolumename disk1

where desiredvolumename is the name yo wish to assign the drive