Syntax highlight static PHP functions in Visual Studio Code in a different color?

Question

I'm working with php classes in Visual Studio Code and would like to augment the syntax highlighting so that static functions in classes have a (slightly) different color than regular functions.

I've tried to achive this using Textmate selectors and a custom user setting like this:

"editor.tokenColorCustomizations" : {
    "textMateRules": [{
        "name": "Highlight static functions",
        "scope": ["meta.function.php storage.modifier.php", "storage.type.function.php"],
        "settings": {
            "foreground": "#FF0000"
        }
    }]
}

But this results in all functions and their modifiers being red:

Is there any way I can single out static functions only?