Parent object not showing - serialized with the same hierarchy in client calling - message contract

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C#

WCF

WCFServices

WCFService

Dears,

I am trying to use message contracts in WCF and i have a parent object with two sub objects in some method and after consuming the service from a test client, the method accepts only the sub objects as input and ignores the parent object!

Example:
WCF Method:

public GetEmployeeResponse GetEmployee_MessageContract(GetEmployeeRequest getEmployeeRequest)
{            
    //Some code and return getEmployeeResponse;
}

GetEmployeeRequest:

[MessageContract(IsWrapped =true, WrapperName = "GetEmployeeRequestObjectWrapped", WrapperNamespace ="http://www.test.com")]
    public class GetEmployeeRequest
    {
        [MessageHeader(Namespace = "http://www.test.com", Name = "AuthenticationHeaderObject")]
        public AuthenticationHeader AuthenticationHeader { get; set; }


        [MessageBodyMember(Namespace = "http://www.test.com", Name = "EMPID")]
        public int Id { get; set; }
    }

AuthenticationHeader:

[DataContract]
    public class AuthenticationHeader
    {
        [DataMember(Name = "KEY", Order =1)]
        public string UserName { get; set; }

        [DataMember(Name = "PASSWORD", Order = 2)]
        public string Password { get; set; }
    }

The MAIN issue now is that while consuming this method from a client app i am getting the following in the service reference.cs file:
Method header is as following:

GetEmployee_MessageContract(EmployeeService_Client.EmployeeService.AuthenticationHeader AuthenticationHeaderObject, int EMPID)

I expect it to be like

GetEmployee_MessageContract(EmployeeService_Client.EmployeeService.GetEmployeeRequest GetEmployeeRequest)

So what is the problem with the above code?

What I have tried:

i tried using serializable in stead of DataContract but still the issue there?