Cannot use Stored Procedure in SQL Server 2012 within VS2013 Report Designer, always returns blank?

Question

I'm attempting to create a parameterized report within a C# application. When I go to the Data Source Designer, I can select preview, and see the appropriate data just fine. However, when I attempt to create a report with the stored procedure, the report ends up being blank, as if no rows are returned

If I create a brand new report, without the parameters, it still returns blank. However, my views and tables pull just fine.

Any ideas?

EDIT

Code Attempt 1

ALTER PROCEDURE [dbo].[getReportData] 
@minimumDate DATE = '1900-01-01', 
@maximumDate DATE = '2100-12-31',
@PO INT = null,
@glCode INT = null,
@merchant INT = null,
@employee INT = null
AS
BEGIN
SET NOCOUNT ON;

SELECT  dbo.transactions.date_purchased, 
        dbo.transactions.description, 
        dbo.transactions.purchase_order_number, 
        dbo.transaction_codes.transaction_code, 
        dbo.merchants.merchant, 
        dbo.transactions.amount, 
        dbo.employees.first_name + ' ' + dbo.employees.last_name AS employee
FROM    dbo.transactions 
      INNER JOIN dbo.transaction_codes ON dbo.transactions.accounting_code = dbo.transaction_codes.id    
      INNER JOIN dbo.merchants ON dbo.transactions.merchant_id = dbo.merchants.id 
      INNER JOIN dbo.employees ON dbo.transactions.employee_id = dbo.employees.id
WHERE   
        (dbo.transactions.date_purchased BETWEEN @minimumDate AND @maximumDate) AND
        (@employee IS NULL or dbo.transactions.employee_id IN(@employee)) AND
        (@po is null or dbo.transactions.purchase_order_number = @PO) AND (@merchant is null or dbo.transactions.merchant_id IN(@merchant)) AND
        (@glCode is null or dbo.transactions.accounting_code IN(@glCode))




END

Without parameters

CREATE PROCEDURE getData
AS
BEGIN
SET NOCOUNT ON;

    SELECT  dbo.transactions.date_purchased, 
        dbo.transactions.description, 
        dbo.transactions.purchase_order_number, 
        dbo.transaction_codes.transaction_code, 
        dbo.merchants.merchant, 
        dbo.transactions.amount, 
        dbo.employees.first_name + ' ' + dbo.employees.last_name AS employee
FROM    dbo.transactions INNER JOIN
        dbo.transaction_codes ON dbo.transactions.accounting_code = dbo.transaction_codes.id INNER JOIN
        dbo.merchants ON dbo.transactions.merchant_id = dbo.merchants.id INNER JOIN
        dbo.employees ON dbo.transactions.employee_id = dbo.employees.id
END
GO

Answer 1

Next thing I would try is a report with an embedded query to see if data is returned. Perhaps, nothing will be returned but something might click for you along the way.