Visual Studio Code Client Capabilities: What about FoldingRange?

I am working on an extension for Visual Studio Code, and I am using the "new" and fancy LanguageServerProtocol. The initialize request of the client (i.e., VS Code) informs the server (i.e., my extension) about its capabilities. However, the TextDocument.FoldingRange client capability is missing form the initialize-request. Consequently, the FoldingRange Request is never sent to the server.

In VS Code, editor.folding is true, and editor.foldingStrategy is set to auto. Following the documentation, I was under the impression that language specific code folding is supported. Is there some kind of setting or whatever (maybe in the package.json or extension.ts) which I have to activate in order for foldingRange support?

Thanks, f_max