I have the following classes:

public class Account
{
       public Account()
        {
            Addresses = new List<Address>();
        }
        public string Id { get; set; }
        public string Firstname { get; set; }
        public string AcctName { get; set; }
        public string Lname { get; set; }
        public string AcctStatCd { get; set; }
        public string MCatCd { get; set; }
        public string Name { get; set; }
        public string CtryCd { get; set; }
        public string HQFldCd { get; set; }

        public ICollection<Address> Addresses { get; private set; }
        public Guid MailingAddressId {get; set;}
        public Address MailingAddress {get; set;}
}

public class Address
{
        public Guid Id { get; set; }
        public string AccountId { get; set;}

        public string Line1 { get; set; }
        public string Line2 { get; set; }
        public string City { get; set; }
        public string StateProvinceCode { get; set; }
        public string CountryCode { get; set; }
        public string PostalCode { get; set; }
        public int AddressTypeCode { get; set; }
}

The idea here is that an Account has many addresses but only one is the default mailing address.  A mailing address is required (although I may just have to enforce that as part of my business rules.)

I have tried all sorts of mapping scenarios but can not seem to get this to work once I add in the MailingAddress piece.  Here is my latest attempt:

    public class NTMAAContext : DbContext
    {
        public IDbSet<Account> Accounts { get; set; }
        public IDbSet<Address> Addresses { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            this.Configuration.LazyLoadingEnabled = false;

            modelBuilder.Configurations.Add(new ConfigureAccounts());
            modelBuilder.Configurations.Add(new ConfigureAddresses());
        }

        public NTMAAContext(string connectionString) : base(connectionString)
        {}

    }

    public class ConfigureAccounts : EntityTypeConfiguration<Account>
    {
        public ConfigureAccounts()
        {
            ToTable("missacct");
            HasKey(m => m.Id);
            Property(m => m.Id).HasColumnName("acctno");
            Property(m => m.Firstname).HasColumnName("Fname");
            Property(m => m.MailingAddressId).HasColumnName("mailingaddressguid");
            HasMany(m => m.Addresses).WithRequired().HasForeignKey(a => a.AccountId);
            HasRequired(m => m.MailingAddress).WithRequiredPrincipal();
        }
    }

    public class ConfigureAddresses : EntityTypeConfiguration<Address>
    {
        public ConfigureAddresses()
        {
            ToTable("missaddr");
            HasKey(m => m.Id);
            Property(m => m.Id).HasColumnName("guid");
            Property(m => m.AccountId).HasColumnName("acctno");
            Property(m => m.CountryCode).HasColumnName("ctrycd");
            Property(m => m.Line1).HasColumnName("addr1");
            Property(m => m.Line2).HasColumnName("addr2");
            Property(m => m.PostalCode).HasColumnName("zip");
            Property(m => m.StateProvinceCode).HasColumnName("stprov");
        }
    }

}

I have tried adding .Map to the .WithRequiredPrincipal but that hasn't really worked well.

So, depending on what I try, I either get an error when queyring the data or when trying to add a new account.  Sometimes I'm getting something about unable to determine order ... (usually when I have the .WithRequiredPrincipal stuff in place) or I get an error about an invalid key Account_Id (if I don't add any kind of .Map() to .WithRequiredPrincipal) or acctno already defined if I do try to use a mapping.

Does anyone know how to accomplish something like this?  Is it even possible?

Thanks for your help.