Thank you for your answer.
The C++/Python codelets are, well, written in C++ and Python, while Unity is using C# as the interface. From the documentation and the code I understand, that the sample Unity-Project is using the C-API to communicate with the Isaac Engine. As I mentioned, low-level descriptions on how to use the C-API is provided but since Unity is a major part of the environment and most people probably want to use it and modify it (since as of now omniverse is only as a preview available) it would be great if there was a simple guide on how to add custom nodes to the Unity-side.
Currently you have to somehow understand the (still well written) code in Unity and manage not to oversee anything, and with luck your node will talk to isaac, which I unfortunately didn’t have :(. It’s not really productive and I eventually had to put Isaac to side and use my own communication framework, which I implemented with GRPC.