Apple RAID Card after System Disk Failure: Volume visible but not mountable

Hi,

Im running a Mac Pro with 10.5.8. Server has a workgroup server. The Mac Pro is equipped with a Apple RAID Card running three 1TB SATA Drives and a SAS drive for the System. The three 1TB drives are used by a RAID5 to store the data the SAS drive was used for the system. After a power failure the SAS drive was dead and I installed a new drive and reinstalled the system with the DVDs that were in the box. After that the RAID5 is not mounted by the system anymore although I can sea it in the RAID Utility but not with its volume name but with the name R2V1.
What can I do to save the data on that RAID?

Thanks
Phil