Motorola L7e and OSX iCal sync

I've just got a Motorola L7e on Orange. I've previously had an L7 and
still have a V3. Both of these have been entirely painless to sync
with my Mac (running 10.4.8).: I just taught it they existed then told
iSync to do its thing and it worked.

The L7e works for contacts, but refuses to sync the calendar at all:
iSync warns that "the phone could not store some of your calendar
events" and nothing ends up in the phone.

Is there anything I can do about this, or should I just go back to the
v3, which worked?

--tim