It takes a while until hours are known in the international travel planner, of Italy. These will soon be known by, among others, OEBB - SBB - DB BAHN.

Know that you can easily reserve surcharges for domestic trains in Italy via the OEBB site.

You can use the TRENITALIA train planner for hours.

Hi Bren, you mean you contacted our Customer Support team? I am not part of Customer Support but happy to look into it and see if I can assist you.
Did you book your reservations already? Just note that the reservations are not meant to appear in the app. Your (mobile) pass in the app and reservations are two separate things. If you are being checked by train staff, you just show your mobile pass in the app and your reservations (either paper or e-tickets in your email).
If you can't find the journey in the app, you can add it manually. Here is the instruction guide on how to do that:

The next update of the schedules will be coming Thursday.

For the rather short trip Sal->Nap use the local/regional train without any need to REServe or pay extra. In fact-if you have a pass with traveldays and this is only trip to do that day-a local ticket is much, much cheaper. There is also another private line-always payable- that stops at the Pompeii ruins so you can do the obligatory sightsee then/there.

Les agradezco la respuesta, ya ví que pueden agregarse manualmente los viajes en la app, pero aún no aparecen los horarios para esa fecha, para podés verlos y cargarlos. Espero al jueves, ojalá los carguen así puedo proceder a comprar el aéreo.

Muchas gracias por sus respuestas