Mirrored RAID set deletion

Hi all,
I've set up two USB disks as a mirrored RAID set connected to my MacBook.
Now, I want to remove this RAID set (since it doesn't work so well for me).
In the manuals, Disk Utility is said to split nicely a mirrored RAID set, resulting in two disks with the same contents, when removing a mirrored RAID set.
However, when I try to do it, Disk Utility warns me that all data on the disks will be lost (which should not be the case...).
I can't afford to loose all data (120GB of photos), and I can't easily make a backup (120GB of data is tough to backup !)
Who should I trust ? Disk Utility or the manual for Disk Utility ?
Will my data be lost or not when I delete this mirrored RAID set ?
I need an authoritative answer... Could someone help me ?
Thanks,
Chris

Thanks for your advice... but if no RAID disk is plugged in, the RAID does NOT show in Disk Utility.
As I understand it, the partition scheme is different when using RAID... So a disk that is part of a RAID set has to be modified to get out of the mirror...
But it seems Disk Utility cannot disconnect a single disk from the RAID.
My RAID is now out of sync, and I won't attempt to resync it again...
So I would like to remove the whole RAID thing, and just get two disks, one that will be reformated, and one where all the data should be kept...
Later this week, I'll have access to another (afaik Firewire) disk... So I'll make a backup and simply try to delete the RAID... If it goes wild, I'll have that backup to recover.
I'll keep you posted if I can.
However, things should be made clear somewhere : either in the docs or in Disk Utility... I submitted some comments about the documentation on apple's website.
Bye
Chris

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