Package ASP.NET Service with npm frontend into installer

Question

i'm having a hard time these days... I start from the beginning:

I am developing a dotnet(6)-Service containing a web-frontend. I am using Visual Studio (2022). If i build my project or deploy it, i want to include the npm-build-output. This really is not a problem, there is a bunch of guides all over the internet. They have one thing in common: They do what they should do. I love all of them. One example: https://www.meziantou.net/running-npm-tasks-when-building-a-dotnet-project.htm

But i start to struggle here: I want to create an installer containing the dotnet-output PLUS the npm output. I use Visual Studio Installer Project. No matter what i do, it always just packages the dotnet-build-output. It just ignores the npm-build-stuff that is in the exact same output folder.

If i build inside VS, my output is: Release +-net6.0 +-runtimes +-(some languages) +-WebConfig +-build (containing npm-Frontend-build-result) +-exe+dlls

If i publish from inside VS, the result is exacly the same.

If i run "build installer", it contains everything but the WebConfig-Frontend. My installer-Config looks like this:

Can someone point me to what i am doing wrong?