The Valcom 2924 can appear like a CO line, providing battery ,dial tone and optional ringing. You will want to connect it to an FXO port, not FXS.
This makes your dialplan easier. Configure that FXO port as a loop-start trunk. Assign a voice grouped-trunk to it with the dialplan of the Valcom, perhaps with a leading pad digit to match the number of digits in your dialplan.
So, if you set the Valcom for 2-digit dial plan where 10 through 33 are the speakers, then your config might look like this:
voice trunk T10 type analog supervision loop-start
trunk-number 2222 ! <- This is the extension or group where ring-in directs
connect fxo 0/1
match dnis 33XX substitute XX
voice grouped-trunk valcom-tg
To page, dial 3310 through 3333. If the paging system has "ring-in" configured to reach the VoIP system, then configure a call center, ring group, or extension on the 7100 with an extension matching the trunk-number configured, 2222 in example. When the Valcom applies ringing voltage to the FXO, then that destination will ring.
For zones, etc. modify the dial plan to allow the appropriate pattern.
Thanks for the help. This worked like a charm.