Integration Services :: Execution Of SP In SSIS Returns Nothing

Until now I've been looking for a possible solution to the execution of a sp from SSIS, but anything seems to work. I´ve got a sp: CREATE PROCEDURE [DBO].[SPIDENTIFIERS] @IDENT NVARCHAR(MAX) OUTPUT

What I need is to save the result in a variable that I've created in SSIS. This is the configuration that I used to try to do it.In the parameter set section I have also used the Direction as Output or ReturnValue but I received a error message. Just to try I put a Script Task to chek the value, but as you can see this is empty.With the Direction Ouput or ReturnValue I've got this:

[Execute SQL Task] Error: Executing the query "EXECUTE spIdentifiers ? OUTPUT;" failed with the following error:

"El valor no está dentro del intervalo esperado.". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly.