I think we both own the same model Que Firewire burner. I initially had problems with it in Jaguar also (never in 10.1). Jaguar does indeed seem to be much flakier with firewire support than 10.1 was. (Don't get me started on the firewire nightmares I'm having with 10.2 and Final Cut Pro!)
Anyway, when are you plugging in and powering up your burner? I've found that I can only get 10.2 to recognize my burner when I am already booted up, then plug in the burner to the mac, then turn the burner power on, THEN start Toast. Have you tried this? This is the only method that works for me with this burner. Try it and let me know if Toast recognizes it.
As for firewire HDs (I have 4 - all different brands and all the same problem in 10.2), I can only get Jaguar to recognize them if they are plugged in and turned on BEFORE booting. Go figure. Why in the world was 10.1's firewire support flawless and Jaguar's is worse than Os 9.0????