I'm not sure whether your question is how to use ITT in GPA 4.0 for instrumenting your code, or how to get GPA to show the different levels in Platform Analyzer.
So a couple of hints that may be helpful:
GPA has some examples showing nested ITT calls when instrumenting your code. I would recommend that you look at these if your question is about how to use ITT (it's possible your calls are not "nested" as ITT/GPA expects)
You should also look at domains and the GPA profiles, as by default we limit the amount of data GPA collects. Please list the profile options you've specified in "general" and "domains"
Please provide some of the ITT code that you've used for your instrumentation, and I can compare this with some "best practices" that we've developed.
Hopefully this helped... After you've looked at these, I'll await follow-up questions from you. Regards,