Hi Pieter and anyone else following this discussion.
After some additional troubleshooting, I've discovered that either the
Expresscard or the Expresscard adapter in my M1210 is the culprit in
this problem. I hope it's the card, because at least I can throw that
out :)
I got desperate and tried out the whole setup in Windows (*sigh*), and
it didn't work there either.
Interestingly, the onboard Ricoh firewire works perfectly - it's total
failure to work at all in Linux was the start of this quest, so I'm a
bit bewildered.
Anyway, thanks to everyone for the help and goodwill.
Chris