My Book Essential not detected by Ghost 14

I bought Ghost 14 and a WD My Book Essentail 500Gb USB 2.0 to provide a backup solution for my Dell Dimension running Windows XP SP3.

 

All seemed to go well, and last night I successfully ran a backup job creating a recovery point and two drive backups on the WD disk. Today I created a customised SRD (using the Automatic option), and successfully ran the driver validation tool.

 

However, on booting from the SRD, the WD disk is not detected; so a restore in the case of disaster recovery is not possible.

 

I am guessing that this is a driver issue; does anyone have a solution or advice?

 

Many thanks

Mike.