RAID Degraded - how mount the disk as standard bootable disk


My mirroring RAID was degraded, disk utility was not abel to rebuilt the RAID, I was wondering if someone knew how to use diskutil (the terminal command, the GUI utility is limited to simple functions) to repair one of two drives in a RAID array.
After many trying I've delete the RAID :-( now I have the two slices and I'm not able to mount it

In order to repair the raid without reformatting (data is probably all still there) I'm thinking I need help in three things;
Repair a disk slice individually.
Flag disk2 as a raid slice--I don't know how to set this property, maybe "mount"?
Create a mountpoint in /Volumes that is raid and then attach the two repaired slices to that so it appears as one logical volume.

Can any terminal master tell me how to do this?
Otherwise, is there any software that can repair a raid without reformat?
the drive appear like this:

diskutil list
#: type name size identifier
0: Apple_partition_scheme *76.7 GB disk0
1: Apple_partition_map 31.5 KB disk0s1
2: Apple_Driver_OpenFirmware 512.0 KB disk0s2
3: Apple_Boot 128.0 MB disk0s3
4: Apple_RAID_OfflineV2 76.6 GB disk0s4
#: type name size identifier
0: Apple_partition_scheme *76.7 GB disk1
1: Apple_partition_map 31.5 KB disk1s1
2: Apple_Driver_OpenFirmware 512.0 KB disk1s2
3: Apple_Boot 128.0 MB disk1s3
4: Apple_RAID_OfflineV2 76.6 GB disk1s4
OK, how to figure this out. Let's assume you only have two disks (it will make the example easier to understand). All of this is from the command line

diskutil list

You will see three disks, probably "/dev/disk0", "/dev/disk1", and "/dev/disk2". One of them is not a physical device, but is made up from the other two being mirrored. That one will have the name of your disk. If that was "/dev/disk2", run the following command:

diskutil checkRAID disk2

In "status", you will see "degraded" and one of the two 'slices' (#0 or #1) will have "Failed" (or something like that) for a status code. Now, let's say that disk0 had a status of "OK" and disk1 was the bad guy; run the following command:

diskutil repairMirror disk2 1 disk0 disk1

This says you want to repair a mirrored disk. The "virtual" disk is disk2, the drive that failed was slice #1 and you're going to copy from disk0 (the good one) to disk1 (the failed one). This process can take hours depending on size of disk and speed and what else is going on on the system. To see how far along it is, do another "diskutil checkRaid disk2" command.
Thanks for the reply, but the problem was that I incidentally broken the raid and the "third" disk was disappear, so now I have only the two slices without the "virtual raid disk".
I'm unable to mount the slices and if I try to rebuild a raid I've to format...
I try also to rebuild a mirror without reformatting:

diskutil enableRAID mirror disk0

but the reply of terminal was an error (search for a volume not a disk)

Any idea to convert the slice in a normal disk standalone?