[X4U] Missing slice in RAID 0 setup

[alexandre]

Hi

I'll try and make this as precise as possible!

I'm running 10.8.4 on a 2010 MacPro. I have two striped RAID sets, one for
files (2 x 3TB) and one for Time Machine backups (2 x 3TB).
Last night, I did a Time Machine backup and then started a complete clone
using SuperDuper of the RAID containing my data. When I got home this
evening, I had a typical OS alert, telling me the disk  hadn't been
ejected properly. I'm presuming it was my data RAID (the source), as it
has disappeared from my desktop.

I booted from an admin account on the SSD and was able to open Disk
Utility (I can't log in to any user accounts that are on the missing RAID,
obviously).

In DU, in the left panel, I can only see one slice (3TB) and in the main
panel:

6 TB - "Monster Data" - Striped RAID set					Offline
	3 TB - RAID slice (disk1s2)
	RAID slice (2785D29A-5C1D-B0F1-3B0544CA0133) 	Missing

Can anybody tell me what is wrong? How can I get the missing slice back?

I'm not too worried(!) since I have an up-to-date Time Machine backup and
a clone but I'd rather repair the current setup than do a restore.

Any help is much appreciated!

Regards, Alexandre