Map struct as type (which can be null)

I have struct

one that wraps decimal

so I can use EditorTemplates, have a security type, expand in the future to add Currency

, etc. etc.:

public struct Price
{
    private readonly decimal value;

    public Price(decimal value)
    {
        this.value = value;
    }

    public static implicit operator Price(decimal value)
    {
        return new Price(value);
    }

    public static explicit operator decimal(Price price)
    {
        return price.value;
    }
}

      

        
        
        
      

    

This is then used in many types that are rendered using Fluent NHibernate, for example:

public class SomeEntity
{
    public virtual int Id { get; protected set; }
    public virtual Price SomePrice { get; set; }
    public virtual Price? NullablePrice { get; set; }
}

      

        
        
        
      

    

How can I tell FNH that when I do

public SomeEntityMap()
{
    this.Id(x => x.Id);
    this.Map(x => x.SomePrice);
    this.Map(x => x.NullablePrice);
}

      

        
        
        
      

    

that it should just be treated as decimal

and Nullable<decimal>

accordingly?

Preferably it would be without the need to edit every mapping, so I'd rather not use IUserType

it as it requires (I think) placing it everywhere

this.Map(x => x.SomePrice).CustomType<PriceType>();
this.Map(x => x.NullablePrice).CustomType<NullablePriceType>();