Returning Parameter Values From Stored Procedure

I am having trouble using Output parameters. I have set up an Execute SQL Task to call a Stored Procedure. I am passing an input parameter and indicating 1 global variable for output to retrieve a unique value from the stored procedure call. When I execute the step, it completes successfully but nothing is returned in my output parameter for the unique value??? Below is the call that I use:

EXEC SYS_GENERATE_ID ?

-in the Execute SQL Task I click the Parameters button to set up the input:
Status = Parameter1
and the Output Variable Type:
Rowset = GUID.

the stored procedure:
CREATE PROCEDURE dbo.SYS_GENERATE_ID
(@Statusvarchar(20),
@GUID uniqueidentifier = NULL OUTPUT)
AS
BEGIN
SET @GUID = NEWID()
INSERT INTO dbo.ACTIVITY (GUID, STATUS)
VALUES (@GUID, @Status)
SET @GUID = convert(varchar(50), @GUID)
RETURN @@ERROR
END

A table is correctly populated but the GUID value does not make it back to the calling task??? The Global Variable Type under Package Properties has been changed to "Dispatch" and the value is "Not Displayable"???
Any help that is offered will be appreciated GREATLY!!