ADO Net Source

I'm using the ADO Net Source with a SQL Command for the Data Access Mode. I need to use one parameter. I can use the expression editor to set up the sql query with the parameter, but then what would I enter for the SQL Command Text where the SQL Query goes? I tried entering the query with the ? for the parameter but that doesn't work. Do I need to enter the query here or should I be entering somethign else since I have the query setup in the Expressions of the Data flow in the control flow tab?

Thanks