Changing from RAID 1 to RAID 5

I am planning on adding a few hard drives to my Dell server running Winnt 4 and Exchange 5.5. I am currently using disk mirroring and would like to switch to disk striping with parity. Is this possible for a production server WITHOUT losing data?I have a full backup but….. F.Y.I. I plan on breaking the mirror, making some slight partition size changes with Server Magic (system partition is too small) then creating a stripe set from the first HDD to the other 4.

Thanks,
Kurt G.