Plextor 708 and firewire problems

I bought the DatOptic internal firewire conversion kits and converted 4 of my burners over to firewire.I can burn 3 different compilations on 3 burners now with no slowdown BUT the plextor doesnt get recognized on the firewire controllers.I tried switching from master to slave to no avail.Anyone have any ideas why it wont recognize it?