How to exec a stored procedure with certain parameters only?

Hi folk!

I have a stored procedure with 3 input parameters.
All the parameters have their defaults.
I need to execute the stored procedure with any combination of the defined parameters.
E.g.
    - EXEC pMyTestProcedure @inFirstParam = "Hello", @inSecondParam = "Folk";
    - EXEC pMyTestProcedure @inFirstParam = "Hello", @inThirdParam = 7;
    - EXEC pMyTestProcedure @inSecondParam = "Folk", @inThirdParam = 7;
-----
CREATE PROCEDURE pMyTestProcedure
   @inFirstParam     VARCHAR(100)   = NULL
   ,@inSecondParam   VARCHAR(100)   = NULL
   ,@inThirdParam    INTEGER        = NULL
AS
BEGIN
SET NOCOUNT ON;

INSERT INTO tMyTestTable
(
   Col1
   ,Col2
   ,Col3
)
VALUES
(
   @inFirstParam
   ,@inSecondParam
   ,@inThirdParam
);
END;
-----
In my package I have a txt file as an input, and I need to process each row from the file: read a row, pass it to the stored procedure, exec the stored procedure.
I understand that I can use other approches to accomplish the goal (load the txt into the table), but I would like to make the above approach clear to me.
So, in my case I am using an "OLE DB Command" in order to execute the SP, and I have encountered a problem.
The input txt has only two columns (First_Col, Third_Col), but the procedure has three input parameters.
My purpose is to map:
 - First_Col to @inFirstParam;
 - Third_Col to @inThirdParam;
In spite of the fact that @inSecondParam has its default value (NULL) in the procedure code, I cannot execute the next code in the "OLE DB Command" component:
EXEC pTestParameters
   @inFirstParam     = ?
   ,@inThirdParam    = ?
;
This component does not understand that I want to skip the second procedure parameter and, when being executed, it replaces @inThirdParam by @inSecondParam.
So, the SQL Server gets the call as:
EXEC pTestParameters
   @inFirstParam    = First_Col
   ,@inSecondParam  = Third_Col
;
Obviously, this behaviour is completely unbecoming to me.
----
As a possible solution I consider using "Script Component".
Do you have any ideas how to get over the problem?
Thank you!