//Use the GetFundInstructionExecution 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 instructions = client.GetFundInstructionExecutions(new BFSServiceReference.GetFundInstructionExecutionRequest()
{
    Credentials = credentials,

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

    Args = new BFSServiceReference.GetFundInstructionExecutionArgs()
    {
        BrickIds = new []
        {
            new Guid("ea3f658e-28f7-46b9-a45e-99b0f2e1a1ff"), 
        }
    },
    Fields = new BFSServiceReference.GetFundInstructionExecutionFields()
    {
        BrickId = true,  
        MarketplaceOrderNo= true,
        ExecutionNAV= true
    },
});

foreach (var c in instructions.Result)
{
    Console.WriteLine(c.BrickId + ", " 
        + c.MarketplaceOrderNo  + ", "
        + c.ExecutionNAV);
}