I've just started the installation of the Denon today, and I will try tomorrow how to make works the bi amp zone, my intention is to have a 5.1 zone in room A, from a DVD (or a Blue-ray in a future) source, and another stereo zone in a room B, from another audio source (mostly CDs). It seems this is possible, using the Surround Back/Amp Assign, to connect the speakers in zone B.
If anybody have experience about how this should be configured, please send me a tip, the owner manual isn't very clear about this.