two-way voice module and paging

I'm putting together a system and trying to understand the functionality of the two-way voice module (10A11-1) along with the speaker-microphone module (28A00-1 or 2) for paging.  As I understand it, the only way to use it for local paging is to have your Omni connected through the RJ-11 jack to your main home line, and then use one of those main line phones to dial in (*836).  My understanding is that you would connect the speaker/microphones in series back to the two-way voice, with the additional option of connecting to a whole home audio system.
Assuming this is correct, does this all go off the rails if you don't have the Omni connected to a POTS line?  I have FiOS for voice, so I don't want to use that for alarm monitoring - instead I will use one of the IP/Cellular options which are out there (Ipdatatel, Telguard).  So then I wouldn't be able to use the Omni for paging?  Or is there a way to hook the Omni into the local, FiOS voice network without that being the primary method for communication with the central station (which I would want to be the IP/Cellular board)?
Also, anyone use the Omni for paging and have general feedback?