Reading FromUri and FromBody at the same time

A post body is typically a URI string like this:

Message=foobar&TestingMode=true

You have to make sure that the HTTP header contains

Content-Type: application/x-www-form-urlencoded

EDIT: Because it’s still not working, I created a full example myself.
It prints the correct data.
I also used .NET 4.5 RC.

// server-side
public class ValuesController : ApiController {
    [HttpPost]
    public string PushMessage([FromUri] string x, [FromUri] string y, [FromBody] Person p) {
        return p.ToString();
    }
}

public class Person {
    public string Name { get; set; }
    public int Age { get; set; }

    public override string ToString() {
        return this.Name + ": " + this.Age;
    }
}

// client-side
public class Program {
    private static readonly string URL = "http://localhost:6299/api/values/PushMessage?x=asd&y=qwe";

    public static void Main(string[] args) {
        NameValueCollection data = new NameValueCollection();
        data.Add("Name", "Johannes");
        data.Add("Age", "24");

        WebClient client = new WebClient();
        client.UploadValuesCompleted += UploadValuesCompleted;
        client.Headers["Content-Type"] = "application/x-www-form-urlencoded";
        Task t = client.UploadValuesTaskAsync(new Uri(URL), "POST", data);
        t.Wait();
    }

    private static void UploadValuesCompleted(object sender, UploadValuesCompletedEventArgs e) {
        Console.WriteLine(Encoding.ASCII.GetString(e.Result));
    }
}