To my humble knowledge 1394 is a bus system with each of the participants
being initator and receipient.
So why not analyze an interface's protocol by simply inserting a (Linux-)PC
between the Windows-PC running the driver and the firewire interface, which
acts as a thru-device and protocols everything going win <-> firewire device ?
For someone with better knowledge on 1394 than me it should be a possible to
get the protocol that way on a rainy weekend.
My two cents,
Ralf