Yes thats right, you have configured your soundcard to be the audio output from your computer. In Nuendo the audio output will be sent to the firewire port of the H8000Fw. So have to route your audio through the H8000 to get the audio output.
For illustration heres the routing
h8000(analog in 1 2) — DSP A —-Firewire Out 1-2—Cubase/Nuendo
Cubase/Nuendo —Firewire 1-2 In —DSP (A or B)
Main Outs 1-2 —-Analog Outs 1-2—Speakers
