I have already created two RAID-1 (or RAID-0) volumes. Can I create a new RAID-0 ( or RAID-1) out of these two RAID sets?
No, you can only create RAIDs out of hard disks, not RAID sets.
Creating a RAID out of RAID sets is not supported.
That means that RAID0+1 and RAID1+0 are not supported on the Ciphertex NAS.