Originally Posted by David the H.
You can start synaptic with 'synaptic --add-cdrom /path/to/cd'. I believe that should let you use your external drive. I don't have any package cds though, so I can't test it for you.
(I discovered this by running 'synaptic --help', BTW).
David - thanks so much for this answer. I looked for 2 or 3
days, including the synaptic man page... as it were, having
never seen any mention of an --add-cdrom option Im still not
sure this is available in my current version.
I will look, and thank you again. Possibly I'll need to upgrade.