It's a PCMCIA issue - you have to use the later (v8) PCMCIA drivers
(instead of the v5 that is installed by default) in order to also use USB.
  I haven't attempted an install of a later version (in fact, I don't have
any machines currently running eCS), so I didn't know that the later
version was now the default, but if it is that is excellent.

Thomas (who used to be Stuart)