I have the following serialized XML:

DataDescriptor

      <d5p1:TimePastToInitializeData >
        <d5p1:Hours>2</d5p1:Hours>
        <d5p1:Minutes>10</d5p1:Minutes>
        <d5p1:Seconds>5</d5p1:Seconds>
      </d5p1:TimePastToInitializeData>

      <d5p1:PollRate >
        <d5p1:Hours>2</d5p1:Hours>
        <d5p1:Minutes>10</d5p1:Minutes>
        <d5p1:Seconds>5</d5p1:Seconds>
      </d5p1:PollRate>                                                       

    </Value>
  </KeyValueOfstringanyType>

With this order, the PollRate property is not constructed and the resulting deserialized object has a null value for this field.

If, however, I change the order as follows:

DataDescriptor

      <d5p1:PollRate >
        <d5p1:Hours>2</d5p1:Hours>
        <d5p1:Minutes>10</d5p1:Minutes>
        <d5p1:Seconds>5</d5p1:Seconds>
      </d5p1:PollRate>  

      <d5p1:TimePastToInitializeData >
        <d5p1:Hours>2</d5p1:Hours>
        <d5p1:Minutes>10</d5p1:Minutes>
        <d5p1:Seconds>5</d5p1:Seconds>                   </d5p1:TimePastToInitializeData>                                                                        

    </Value>
  </KeyValueOfstringanyType>

both properties PollRate and TimePastToInitializeData are constructed and initialized properly.

public class DataDescriptor
{
     RefreshRate pastTime;        
        [DataMember]
        public RefreshRate TimePastToInitializeData
        {
            get; set;
        }

     RefreshRate pollRate;
        [DataMember]
        public RefreshRate PollRate
        {           
           get; set;
        }

 [OnDeserializing]
        void Initialize(StreamingContext c)
        {
           // should I do this??

        }
}

And RefreshRate:

[DataContract( Namespace = "http//www.emssatcom.com/occ600")]
    [Serializable]
    public class RefreshRate : Observable
    {
        public RefreshRate()
        { }

        int hours;
        [DataMember]
        public int Hours 
        {
           get; set;
        }

        int mins;
        [DataMember]
        public int Minutes
        {
           get; set;
        }

        int secs;
        [DataMember]
        public int Seconds
        {
            get; set;
        }

        int ms;
        [DataMember]
        public int MilliSeconds
        {
            get; set;
        }              
    }