c# - WCF RIA Entity With Include Not Materializing in Silverlight Client

Question

I'm having an impossible time figuring out why my returned child entities are null for a particular query:

The item has a child property with a 0 or 1 multiplicity called MetaDataItem.

var res = ObjectContext.Contents.Include("MetaDataItem");

This works. I can confirm that res contains 1 instance of MetaDataItem.

On the client:

var loadOperation = _cContext.Load(_cContext.GetItemQuery(itemId.Value)....
Content item = _cContext.Contents.First(c => c.ContentId == itemId.Value);

Here item.MetaDataItem is null instead of containing the one instance.

Here is the metadata class (note that I DO have an include attribute):

[MetadataTypeAttribute(typeof(Content.ContentMetadata))]
public partial class Content
{
    internal sealed class ContentMetadata
     {
         [Include]
         public MetaDataItem MetaDataItem { get; set; }
     }
}

So, why isn't my object populating? What else should I be looking at? Unfortunately, this appears to be where the magic of RIA services occurs, so I can't even really get a handle on attempting to debug the issue. Any help would be most appreciated.