Rename inherited member in Sub class

main.cs

using System.Linq;
using System.Runtime.Serialization;
using ServiceStack;
using ServiceStack.Text;

[DataContract]
public class Parent
{
    [DataMember(Name = "parentItem")]
    public virtual string Item { get; set; }
}

[DataContract]
public class Child : Parent 
{
    [DataMember(Name = "childItem")]
    public override string Item { get; set; }
}

var json1 = new Parent { Item = "parent" }.ToJson();
json1.Print();

var json2 = new Child { Item = "child" }.ToJson();
json2.Print();

packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="ServiceStack.Text" version="5.2.0" targetFramework="net45" />
  <package id="ServiceStack.Client" version="5.2.0" targetFramework="net45" />
  <package id="ServiceStack.Interfaces" version="5.2.0" targetFramework="net45" />
</packages>