optional parameter command object

Using the ADO DataEnvironment... How do I get the optional parameters for a command object to work? I went to the Properties of the command object and named my parameters.. then set required to false and put a value there (basically, the default... this is what MSDN says to do).. but in code, if i dont pass one of the optional parameters, i get an error stating that the required paremeters have not been passed. Is there maybe a placeholder that I need to be using here in my call to the command object..

Help please
-gb

Optional parameters exist in the Stored Procedure where you can set it up:

Code:

---

CREATE PROCEDURE TestProc (@IDCol varchar(11) = NULL) AS
        --If you don't pass the parameter it will be considered as NULL
        IF @IDCol = NULL
            select count(au_id) from authors
        ELSE
            select count(au_id) from authors where au_id = @IDCol

---

this holds true for stored procedures, but what about command objects in the dataenvironment?

In addition to being null if it is not passed to the procedure, can you set a default value other than null.. say a wildcard like %?

Thanks for your response
-gb