"Solution with a Mix of C# and C++" how to?

In this topic I already typed in a powershell script, but now I am trying following command:

"$(build_wrapper)" --out-dir $(SonarOutDir) "$(msbuildPath)\MSBuild.exe" $(SrcDir)\SolutionA.sln /t:Rebuild /nologo /nr:false /t:"Clean" /p:FullRelease=true /p:platform=$(BuildPlatform) /p:configuration=$(BuildConfiguration) /p:VisualStudioVersion="15.0" /p:AppxBundlePlatforms="$(BuildPlatform)" /p:AppxPackageDir="$(Build.ArtifactStagingDirectory)\AppxPackages\\" /p:AppxBundle=Always /p:UapAppxPackageBuildMode=StoreUpload /m

Let’s focus on changing root dir first.
I have tried changing the commands working directory in TFS UI, but that didn’t change anything other than the path to .sln needs to change accordingly, if defined relatively. TFS runs the command from repo as standard. Changing the “Sources root directory” in “Prepare analysis on Sonarqube” from . to anything else gives following error:

java.lang.IllegalStateException: The "build-wrapper-dump.json" file was found but 0 C/C++/Objective-C files were analyzed. Please make sure that:
* you are using the latest version of the build-wrapper and the CFamily analyzer
* you are correctly invoking the scanner with correct configuration
* your compiler is supported
* you are wrapping your build correctly
* you are wrapping a full/clean build
* you are providing the path to the correct build-wrapper output directory
* you are building and analyzing the same source checkout, absolute paths must be identical in build and analysis steps