var client = new SDataClient("http://localhost/sdata/slx/dynamic/-/")
{
    UserName = "admin",
    Password = ""
};

var account = new Account
{
    AccountName = "Test1234567890",
    Type = "Test",
    CAdditionalInfo = new CAdditionalInfo
    {
        Date_of_birth = new DateTime(1978, 10, 26, 0, 0, 0),
        Do_not_call = false
    }
};

client.Post(account);