What OS are you using? You have to go into the adapters bios upon boot up, and select what type of RAID setup you would like, either a span or mirror, and select your drives. If Win9x or better, then it should detect it as a SCSI adapter, and then you can install the diag software and see what type of RAID setup you are using and the status of your RAID.
Just remember when you unplug any of the drives from the adapter to TEST your RAID setup if mirroring, you will need to go into your adapter's bios again and reset the RAID setups and select your drives again. Someone correct me if there is a better way to do this without this step after a two drive failure test?