Unknown Configuration Setting Error on Setting Custom Template Directory

[ghost]

On setting a custom path for the template files in Windows, VS Code throws an error:
Unknown configuration setting

"fileTemplates.templates_dir": "path/to/my/templates"

Looking onto the error traces it shows following dump:

{
	"resource": "path/to/my/AppData/Roaming/Code/User/settings.json",
	"owner": "_generated_diagnostic_collection_name_#1",
	"code": "undefined",
	"severity": 4,
	"message": "Unknown configuration setting",
	"startLineNumber": 11,
	"startColumn": 5,
	"endLineNumber": 11,
	"endColumn": 34
}

Is there something missing when specifying a custom template path?