Why can not do RAID5 under DLT891 and DLT892 in ARCserver2000!!??

[Ayman Altounji]

Dual Channel Wide-Ultra Differential Tape Library Adapter plug into COMPAQ DL580 PIC slot5, then one port connect to TL892(in fact , there are two drives in TL891,so it is DL892), and another port connect to TL891. total it is 3 drives.
ARcserver Tape and RAID option all have been installed on the server.
If I do not create the RAID0 or RAID5, ARCserver2000 can recongrize and the two libraries and appear in the ARC server device manager.
but if I create the RAID0 or RAID5 under the two libraries, It will not.
DO it mean RAID0 or RAID5 can not implement under DLT891 and 892 (3 drives)???
All Arcserver2000 think 891 and 892 as different library type and do not support RAID0/5 of different library type ??