I believe what you are looking for can be done under subscriber management. There is a field called Backup Operator Mailbox. Put the extension that you want the zero out option to go to. There is a catch here, the extension has to match a mailbox on the MM system. If not, the call will not be transferred unless you have "transfer invalid mailbox number" set to yes in the TUI section of the voicemail system configuration. I would advise against setting this field to yes. So if the zero out extension is not a mailbox, you will have to create a bogus mailbox to serve this purpose. This will of course require you to use valuable mailbox licenses to overcome what I feel to be a deficiency in the system. If that is a problem for you, I'd suggest bringing it up with your salesperson.
I have not used the personal operator schedule, but I think it is something probably configured through Subscriber Options. This would be used if you wanted 0 out calls to go to say a receptionist during the day, but to a mailbox after hours. Once the schedule has been set in Subscriber Options, maybe you would then have more options.
Final caveat, depending on your integration and network configuration, you may have to do some special programming on the PBX side to route the call to the appropriate location.
