slnx file not loading platform

I'm trying out the new slnx file format an stumbling across an issue with platforms. In the sln I have something like this:

GlobalSection(SolutionConfigurationPlatforms) = preSolution
	Debug|Clang Win64 = Debug|Clang Win64
	Debug|MSVC Win64 = Debug|MSVC Win64
	Final|Clang Win64 = Final|Clang Win64
	Final|MSVC Win64 = Final|MSVC Win64
	Profiling|Clang Win64 = Profiling|Clang Win64
	Profiling|MSVC Win64 = Profiling|MSVC Win64
EndGlobalSection

I'm mapping that in the slnx as

<Configurations>
    <BuildType Name="Debug" />
    <BuildType Name="Final" />
    <BuildType Name="Profiling" />
    <Platform Name="Clang Win64" />
    <Platform Name="MSVC Win64" />
  </Configurations>

but this fails with the following error: Cannot load project: project does not contain requested configuration Debug|x64. Please verify that .sln file is valid and uses only existing project configurations.

The project references platforms as follows:

<ProjectConfiguration Include="Debug MSVC Win64|x64">
      <Configuration>Debug MSVC Win64</Configuration>
      <Platform>x64</Platform>
    </ProjectConfiguration>
    <ProjectConfiguration Include="Debug Clang Win64|x64">
      <Configuration>Debug Clang Win64</Configuration>
      <Platform>x64</Platform>
    </ProjectConfiguration>
    <ProjectConfiguration Include="Profiling MSVC Win64|x64">
      <Configuration>Profiling MSVC Win64</Configuration>
      <Platform>x64</Platform>
    </ProjectConfiguration>
    <ProjectConfiguration Include="Profiling Clang Win64|x64">
      <Configuration>Profiling Clang Win64</Configuration>
      <Platform>x64</Platform>
    </ProjectConfiguration>
    <ProjectConfiguration Include="Final MSVC Win64|x64">
      <Configuration>Final MSVC Win64</Configuration>
      <Platform>x64</Platform>
    </ProjectConfiguration>
    <ProjectConfiguration Include="Final Clang Win64|x64">
      <Configuration>Final Clang Win64</Configuration>
      <Platform>x64</Platform>
    </ProjectConfiguration>

What am I doing wrong? How should I map these concepts in the new model?

Thanks

Start with the slnx Configurations mapping and compare it with the project's ProjectConfiguration entries, especially the requested Debug|x64 combination. Determine how build types, platforms, and the combined project configuration names are expected to correspond; done means the slnx loads without the configuration error.