AutoMapper: Map null source object to decimal

I need to map an object of type PriceValue to a decimal value and I have the following mapping configured:

public class PriceValue
{
    public decimal Value { get; set; }
    ...
}

...

Mapper.CreateMap<PriceValue, decimal>()
    .ConvertUsing(src => src.Value);

The problem is when src is null an exception is thrown.

What's the best way to configure the mapping so a default(decimal) is returned instead?

via Chebli Mohamed