OSX Boot from DVD - Cannot find My Book for Time Machine

No problems so far with My Book Live being seen by the Macs.  However, when I boot from the DVD to do a restore, Time Machine cannot find My Book.  Is this normal?  The workaround is to connect the My Book directly to the Mac, but this is a bit cumbersome.  TIA.

Could it be the network itself not fully recognized from the installation disc?