Is there a possibility to scan the contents of a .csproj file for certain tags with a custom rule

using: Sonarqube 7.7, Developer edition.

I am trying to trigger a CodeSmell if there is a <HintPath> in the .csproj file.
This could mean the developer linked a DLL directly in stead of using a Nuget reference.
When the Nuget is updated the path to the dll will change and the reference will break.

I tried to make an XPath XML rule but it seems like it is not triggered:

expression
//*[local-name()='HintPath']

filePattern	
/**/*.csproj

message	
Projects should not refer directly to dll's but use Nuget references.

Are *.csproj files excluded automatically?

I hope someone can help me out here, thanx in advance.

Can you post an example of .csproj file where the issue should be detected? Can you also post the debug logs of the analysis when you analyze .csproj file?