AutoMapper: map DTO back to domain object with child objects

Question

Let's say I have two objects I'd like to map:

// Domain objects
public class MyDomainObject
{
    public string SimpleText { get; set; }
    public int SimpleNumber { get; set; }
    public MySubObject ComplexValue { get; set; }
}

public class MySubObject
{
    public int Id { get; set; }
    public string Name { get; set; }
}

// DTOs
public class MyDto
{
    public string SimpleText { get; set; }
    public int SimpleNumber { get; set; }
    public int ComplexValueId { get; set; }
    public string ComplexValueName { get; set; }
}

// Mapping config
Mapper.CreateMap<MyDomainObject, MyDto>();

Ths will work fine without extra configuration because AutoMapper will look at camelcasing and drill down.

Now I'd like to map the DTO back to the domain object:
Mapper.Map<MyDto, MyDomainObject>(dto, domainObj);

What would the best/simplest mapping configuration be to achieve it?