Daaaaar gaat ie weer-ge zijt te VRoeg. Kan pas later. Het is al heel wat dat ze inmiddels tijden hebben weten op hun site te krijgen. Soms 3 mnd tevoor, meestal 2.

Als ge niet al te zeer op enkel het net wat snellere treintje gericht bent: er gaan ook vrijwel elk uur RV=regional Veloce, net als NMBS gewoon zonder REServ. Die rijden dan verder langsheen kust naar Ventimiglia of some naar die 5 aardes (cinqueterre)

Oke, it is my first time with interrail so i am trying to figure out how it exactly works. If there is like always place on a high speed train in august? and when i have to start planning those in, but in your kind reaction i can start planning in june. 

Pass holder seats in Italian domestic trains are not quota-controlled so unless it's a very busy day (such as beginning or end of the holidays), a few days in advance is enough.

It looks like most trains have not been opened for booking yet. Just wait another month. I don't see the 15:10 train yet on www.trenitalia.com (which is a more reliable source for Italian timetables).

By the way, there are also lots of reservation-free regional trains that take just a bit longer, e.g. the one leaving Milano Centrale at 14:25.

In addition, it's cheaper to book Italian day trains via ÖBB (using these steps) so you won't pay any booking fees (Interrail charges an extra 2€ per person and train).

Just to check if i understand it right i have a mobile 1 country pass. So on the site ÖBB i can find the train, select the option interrail and “buy” get tickets and seats on that site with my pass. Do the tickets than go to my email adress or will they appear in the interail app? 
 

You get via ÖBB a PDF and you have to print it (this say the website before booking, I never got reservations for Italy before via ÖBB). 

I see that you are from Belgium, you can also ask SNCB/NMBS International Ticket Desk in Brussel South if they can sell reservations for Italy. If you are travelling now, you can also book at DB, SBB CFF FFS, ÖBB or Trenitalia ticket offices the reservation. 

You will never get reservations in the app, also when you buy it on the app, because the app only shows the Interrail Website. Website and App are two different systems and don’t work together. On the app you have your ticket (the Interrail pass) and on trains were you need reservations, you have to show also the reservation. 

In your case I would use the regional trains, because the time difference between long distance trains and regional trains is minimal on this route (but on regional trains you don’t have a selected seat and if the train is full you have no seat). Or you choose a Intercity train, this will cost only 3€ for the reservation. 

Thank you for the information. So i know now i have te wait at least till june before start planning, the ÖBB is really interesting, i dont need it in the app a pdf is fine as well. I also lives near Brussel south if necessary i can just check their for the trains. And that i best check on trenitalia for the most up to date traintables..
Thanks everyone for your help.
 

Yes indeed, Belgian railways also sell Interrail reservations for Italy, also without booking fee.

I already found the belgium site with all the trains for italy,  i cant just figure out where to activate that i have an interrail pass. But i can call the service center next week to ask them. 

Belgian railways don't sell Italian pass reservations online. Only at the ticket office (at 21 stations) or via phone.

I called the service station in belgium and a very kind lady did all the seat reservations that i needed for me. Great service .