Add '#' to end of file

I have a stored procedure which is called by a vb.net program and the end result of the process is that a text file is generated.  This is the T-SQL code for the stored procedure:

ALTER PROCEDURE [dbo].[udp_INTERCEPT_FILE] @Batch_Num VARCHAR(20)
AS

select col1
 from (

 Select -2 AS row_num, '<V1.0>,"' + substring(@Batch_Num, 11, 1 ) + substring(@Batch_Num, 14, 2) + 'I"' AS col1
 UNION ALL
 Select -1 AS row_num, '*,"' + substring(@Batch_Num, 7, 5) + substring(@Batch_Num, 14, 2) + 'i",,"PONUM",,,"' +
                 + substring(@Batch_Num, 7, 5) + substring(@Batch_Num, 14, 2) + 'i.dat"'
 UNION ALL
 Select  ROW_NUMBER() Over ( order by order_number, line_number,winpart,winpos) AS row_num,
               Cast( (ROW_NUMBER() Over ( order by order_number, line_number,winpart,winpos)) as varchar( 100 )) + ','
             + Cast(Quantity as varchar(25)) + ',0,"IG",'
             + CASE winpart
                   when 'FIXED' then Cast(xwpFixedUnitWidth as varchar(25))
                   else Cast(xwpVentUnitWidth as varchar(25))
                   end + ','
             + CASE winpart
                   when 'FIXED' then Cast(xwpFixedUnitHeight as varchar(25))
                   else Cast(xwpVentUnitHeight as varchar(25))
                   end
              + ',,"'
           + Isnull ( ( select top 1 item_number from pct_order_bom where pct_order_bom.Order_Number = pct_glass_labels.ORDER_NUMBER
             AND pct_order_bom.LINE_Number = pct_glass_labels.LINE_Number
             AND STOCKED = 'SPACER' ), 'Not Found') + '","GAS",,,,,,,,"' + substring(Order_Number,7,6) + '-' + Cast(line_number as varchar(5)) + '"' AS COL1_AFTER_ROW_NUM
 from pct_glass_labels
 where batch_Number = @Batch_Num

 ) as derived
 order by row_num

It works perfectly except for one thing:  I need to have a '#' at the end of the file on a row by itself.  If I add this code:

UNION ALL
SELECT '#'

just before the ") as derived", I get this error:

"All queries combined using UNION, INTERSECT OR EXCEPT must have an equal number of expressions in their target list."

How can I get this '#' added to the end of my file?