deploy-extra-files.xml

<PropertyGroup>  
  <CopyAllFilesToSingleFolderForPackageDependsOn>
    CustomCollectFiles;
    $(CopyAllFilesToSingleFolderForPackageDependsOn);
  </CopyAllFilesToSingleFolderForPackageDependsOn>
  <CopyAllFilesToSingleFolderForMsdeployDependsOn>
    CustomCollectFiles;
    $(CopyAllFilesToSingleFolderForMsdeployDependsOn);
  </CopyAllFilesToSingleFolderForMsdeployDependsOn>
</PropertyGroup>

<Target Name="CustomCollectFiles">  
  <ItemGroup>
    <_CustomFiles Include="dist\**\*" />
    <FilesForPackagingFromProject Include="%(_CustomFiles.Identity)">
      <DestinationRelativePath>dist\%(RecursiveDir)%(Filename)%(Extension)</DestinationRelativePath>
    </FilesForPackagingFromProject>
  </ItemGroup>
</Target>