I am mapping MongoDB documents to C# objects (see [this question](https://stackoverflow.com/q/34729851/3131147) for some background) and everything works fine, however I'm starting to find some entries that are null. The reason being the XML previously just had `<VehicleEntry></VehicleEntry>` tags so it was inserted as 'null' into the array in the BsonDocument.

I can understand that this would be expected behavior, but when I map it to my `VehicleEntry` class that I wrote, it shows up as a null object. In my mapped class I have listed a bunch of BsonDefaultValues and even added a default constructor, but it still appears that if the value is 'null' in the database it will create a 'null' reference object.

How can I set this up to match a null reference to an object with all default values?