so I may have found a reasonable solution; the version of calibre that is available for my current version of Ubuntu (Ubuntu 10.04.2) via synaptic seems to be horribly out of date (0.6.42) whereas the calibre website has version 0.7.53.
The short lesson being: if you can't see your ereader in your distro provided version of calibre, go to the website and get a newer version; it might resolve that (and perhaps a whole host of other issues, as well).
Thanks, and hopefully someone else can find this useful at some point.