How to restore a complete PC backup from a external HD.

Hello.
Yesterday I made a complete windows backup via the Backup an Restore Center
in Vista Ultimate. I saved the complete backup (125Gb) on an external HD
because burning it to DVD would cost me more then 25 DVD's a huge amount of
time! As I wanted to test if I could restore via the backup, I encountered a
problem.

First I started with the Vista setup DVD and chose System Repair. Then setup
asked me to load the driver for my HD's (I have a RAID 10 config), so I did.
Seup then saw my HD's in the correct way. The next step was to click the
option for a complete PC restore in stead of a normal setup. But then setup
looked only on internal HD's or DVD for the backup image and ofcourse could
not find it because it's stored on my external HD. I could not point setup to
look on the external HD becuase there is no option to browse on another
location.

So how can I point setup to use the image on my external HD? It's really a
no go to burn more then 25 DVD's for an image, let aside to restore the image
from 25 DVD's again! I can't believe that Vista's setup has no option to
browse on a alternate location for an image. How can I let setup look for my
image on my external HD?

When I use a normal setup, vista sees my external HD just fine.

Greeting, Ludo Timp, The Netherlands