Passing Varibles into Oracle Username and Password Parameters

I'm using the SQL General component to access my SQL database.  I would like to pass the username and password into the Data Source through Text Boxes and not hard code them in either the Data Source or the SQL General component.

My belief is that this isn't possible, but thought I'd ask before I gave up.

I configured the Data Source on the Administration Console without the Oracle username and passwords set, then set the SQL General component's Authentication Method to Use Username and Password Parameters.  Then I attempted to put PLP variable names into the Username and Password fields, but that didn't work.  I was guessing that it wouldn't when the "password" variable showed up as stars.

Any ideas?

Thank you,
Randy Stegbauer