We do have a detailed guide to drive recovery. That guide is available here :
Drive Encryption Diagnosis and Recovery - Symantec Drive Encryption & PGP Whole Disk Encryption - http://www.symantec.com/docs/TECH149679
Additionally, it sounds like your customer may have a RAID configuration (You mentionend they are a pair). Symantec is very picky about what raid it will support. HARDWARE RAID 0 and RAID 5 should be OK as long as they are not GPT. Software RAID is definitely not supported
Beginning with version 10 of PGP Desktop, PGP Whole Disk Encryption is supported on Windows Server 2003 and Windows Server 2008 on (Hardware) RAID disk drives. PGP WDE supports internal system RAID-1 and RAID-5 formatted with MBR partitioning style only (GPT partitioning style is currently not supported).