Passing business objects as parameters

Let's say you have a business object:

public class Person {
   public string FirstName {get;set;}
   public string LastName {get;set;}

   public Person(string firstName, string lastName) {
      this.FirstName = firstName;
      this.LastName = lastName;
   }
}

I know that if you call a WebMethod that returns a Person object you can refer to its properties on the client by name. For example:

function onWebMethodSuccess(result) {
    alert("Hello " + result.FirstName + " " + result.LastName);
}

But what if I want to pass a Person object as a parameter to a WebMethod?

Does the class Person have a proxy class created on the client like the WebService does? Can I do:

var p = new Person("Joe","Sandwich");
PersonService.CreatePerson(p, onSu ...