WCF deserialization

Please help me out to get this fixed... Its been ages I'm trying to solve this.

I'm writing a wcf service which consumes a third party service as service reference. And this wcf service will be used in a client to send soap xml messages.

While using xml serializer the client code to deserialize an xml file works but some of the properties are null; which worked while using a asmx web service. Please let me know if I'm missing something.

The wcf service is below,

[ServiceBehavior(Namespace = "http://ift.tt/1t4ji3D")]
    [SoapDocumentService(ParameterStyle=SoapParameterStyle.Bare)]    
public class Service : IService
{        
    [SoapDocumentMethod(ParameterStyle=SoapParameterStyle.Bare)]
    public OTA_HotelResNotifRS ReservationNotification(OTA_HotelResNotifRQ OTA_HotelResNotifRQ)
    {
...........
}

[ServiceContract(Namespace = "http://ift.tt/1t4ji3D")]
[XmlSerializerFormat]
public interface IService
{           
    [OperationContract (Action="http://ift.tt/1EncbgQ")]
    [return: MessageParameter(Name = "OTA_HotelResNotifRS")]
    OTA_HotelResNotifRS ReservationNotification(OTA_HotelResNotifRQ OTA_HotelResNotifRQ);        

}

The client code is below

LotusResNotifService.OTA_HotelResNotifRQ OTA_HotelResNotifRQ = new LotusResNotifService.OTA_HotelResNotifRQ();

        XmlRootAttribute xRoot = new XmlRootAttribute();
        xRoot.ElementName = "OTA_HotelResNotifRQ";
        xRoot.IsNullable = true;
        xRoot.Namespace = "http://ift.tt/NpIDks";

        XmlSerializer deserializer = new XmlSerializer(OTA_HotelResNotifRQ.GetType(), xRoot);
        StreamReader reader = new StreamReader(@"D:\HotelResNotifRQ_SOAP_RQ.xml");
        object deserialized = deserializer.Deserialize(reader.BaseStream);
        OTA_HotelResNotifRQ = (LotusResNotifService.OTA_HotelResNotifRQ)deserialized;

The OTA_HotelResNotifRQ has some of the properties returned as null though the xml elements and values are present...