RAID 5 is not possible with this sort of setup. It's all down to the IDE limitations of two drives per IDE channel.
If you want full RAID 5 then you need SCSI and a 'full-on' RAID card.
RAID 0 is a no-no if you want security.
RAID 1 is possible, I have the same setup here and it's all handled in the BIOS, Remember that you won't see the second drive in Windows because the BIOS is using it as a mirrored drive and so all reading/writing is controlled by the RAID card.
Also, Windows will not recognise the RAID array, It just sees one disk of the two disk set.
If you want to do any RAID management you need to install the software which you should be able to get from the Promise website.
Hope that helps.
Gary.