Help please with Arcam 850 zone 2

I recently purchased an Arcam 850. I like the sound, except I can't figure out how to get zone 2 (outside speakers) to play. My inside system is 5.1 and plays perfectly in both stereo straight and surround modes. I have the outside speakers wired to the Zone 2 terminals. In the setup menu, Zone 2 is set to "Follow Z1" and set to "On" as opposed to "Standby". I also have the Zone 2 volume set to 40 db. I also click the Zone button on the front of the amp to Zone 2.  The sound came on once or twice, quite by accident, so I know that it works, somehow. I appreciate any insight as to how to get Zone 2 speakers to play.