I went the .vcxproj file route. Worked like a charm!
For Posterity:
I added a conditional property group
<PropertyGroup Condition=”‘$(DesignTimeBuild)’!=””>
<IntelliSenseCommandline>/Zc:__cplusplus</IntelliSenseCommandline>
</PropertyGroup>
Then i added the value of the property to the AdditionalOptions line
<AdditionalOptions>-x c++ -fconcepts $(IntelliSenseCommandline) %(AdditionalOptions)</AdditionalOptions>
Now it compiles and highlights correctly!
Thank you for the quick support.