//Create a new account with the CreateAccount method
var client = new BFSServiceReference.bfsapiSoapClient();

var credentials = new BFSServiceReference.Credentials()
{
    UserName = bfsusername, //Username of administrative user in your instance of BFS
    Password = bfspassword, //Password of the administrative user in your instance of BFS
};

var response = client.CreateAccounts(new BFSServiceReference.CreateAccountRequest()
{
    Credentials = credentials,

    identify = bfsidentifier, //Identifier is a unique token for your instance of BFS    

    Entities = new[]
    {
        new Account()
        {
			AccountTypeKey = "HoldingAccount",
            Owner = bnuserbrickid,
            OwnerAccountLabel = "Test",
            BaseCurrencyCode = "SEK",
            ExternalReference = "123456789",
            AccountStatus = 1,
            RequestReference = "My system reference",
            AcquisitionValueCalculationMethod = "Average"
        }
    }

});

foreach (var c in response.Entities)
{
    Console.WriteLine(c.AccountNo);
}