Hi Richard,
Did you ever get this working for you?
Did you notice the "--scan" option to jigdo-lite? It might
allow you to use your DVD iso's to avoid downloading a lot
of stuff you already have. I seem to remember that internet
bandwidth was a problem for you.
Note: I believe that the powers-that-be have decided that
supporting the "businesscard" images is not going to be done
in the future. The suggestion is to use "netinst" instead.
It's not much bigger than "businesscard" and it allows a
fairly complete "minimal" installation without requiring
network access, which "businesscard" did not.