Set value in web property bag using REST API

I am trying to manage web properties from property bag using REST API.

It is pretty straightforward how to get the values

var url = "http://ift.tt/1vWTwVP";
$.ajax({
    url: url,
    method: "GET",
    dataType: "json",
    headers: { "Accept": "application/json; odata=verbose" },
    success: successHandler,
    error: errorHandler
});

However, I am unable to set the specific property. Any ideas how to achieve that?

What I have found at MSDN, the AllProperties is available only for read in REST