Hi Damiano Callegari ,
1.First check the system object is passing the its property conenction testing fien or not ,as the its runiing towarrds backend system through GUI for HTML ITS should be passed correctly ,for that use sicf transaction to check wheather the path of the its is correctly given as in sicf its path ,also check the sicf its service is active or not with out that ivac could no tbe processed further ,i got the same issue and got resovled with the above precautionaries.
2. secondly some more information like
an IAC is an internet application component. It runs through the ITS. Check out help.sap.com, http://help.sap.com/saphelp_nw04/helpdata/en/44/216fe21784648ee10000000a1553f7/frameset.htm
An IAC allows you to create an application which looks the way you want it. An IAC is in many ways like a BSP application, the main difference is that an IAC runs through the ITS. The main advantage with the IAC is that you can get the screens created by the ITS, and then modify them to suit your needs.
I would advice you to read Raja webblog Running your first ITS WebGUI application in SAP NetWeaver 04 ABAP Edition - NSP, it is about the integrated ITS. But is should give you a grasp of the process of creating an IAC on the integrated ITS
Hope you get the information correct and solves the issue!
I checked both your points but I cannot find our ITS services.
We have two sap portal installations, one of these with portal 7.0 and other with the version 7.3. They are joined at the same R3 system but I can create a new IAC iView within portal 7.0, but I cannot within version 7.3.
How can I show my ITS services on portal 7.3 (NewiView from Remote) ?
You wont get the standard services of it ,there should be duplication of the standard service for custom development of it in SICF,so create or copy the standard service ,activate it and go ahead with your attempts.
Hope you resolve the issue now!!