There are many different ways that you can go from PSTN to IP and it depends on how you want to do this. You also need to have the tenor setup to register to a sip server/proxy to originate using sip.
Hop-off is only for call that go from IP to PSTN. When you are dealing with SIP, as long as you have the sip server and proxy setup in the tenor, then you need only concern yourself with the tcrg area and how you want to do inbound pstn to IP.
If you need more help, you can contact me directly at firstname.lastname@example.org and we can discuss this some