I like private readonly backing fields because some objects are mostly read-only after creation, and for collections, which rarely need to be set wholesale (instead using collection methods to modify the collection).

For example:

public class BuildingType : DomainEntity
{
        /* rest of class */

        public IEnumerable<ActionType> ActionsGranted
        {
            get { return _actionsGranted; }
        }


        private readonly IList<ActionType> _actionsGranted = new List<ActionType>();
        private readonly Image _buildingTile;

        public virtual Image BuildingTile
        {
            get
            {
                return _buildingTile;
            }
        }
}

But as far as I remember fluent-nhibernate's automapper never had a solution for private readonly backing fields, I'm wondering if that's changed in the last few months.

So here's my question:

How do I configure automapper or create an automapping convention to map private readonly backing fields?