Hi THambrecht,
I only have SONAR X1d, and the Integra-7 VST editor is VST3, so I can't use it in SONAR. What I do instead is to run it in SAVIHost. With this setup, I don't have any connection problems, just that the editor is very slow. The other editor made by K_Take (the Japanese developer) works too, but can be finicky about certain operations (loading expansion sets, reading user tones, which .NET version is used, etc., at least on my computer).
Both editors are just editors anyway, so I don't see it mandatory to integrate them with SONAR.
I find the editors to be good for changing settings but not that great for changing patches. The long drop-down boxes are not very user friendly. The iPad editor is better for that purpose. So I usually change patches on the hardware panel instead.
One thing I did to Integra-7 when using with SONAR is to disable receiving Program Changes and Volume. I have patches and volume stored in Integra-7 and I do not want SONAR to mess with them. In fact, I save the entire studio set to a file (either editor specific or as .syx), one file per song. The advantage is that the Integra-7 settings are independent of the DAW, and the user tone changes are included in the file as well, that means I don't need to save user tones.
In SONAR, for each MIDI track that corresponds to a part in Integra-7, I set the patch to the corresponding studio set part. I think that option appears after installing the INS file.
Hope that helps.