We create our courses and classes with the same name if that helps any.
You've probably already solved this, since the question is old, but it's probably best to create individual courses for each topic. As you've found out, you can't search by class name, only course name. Also, just the course name shows up on the student transcript, not the class name.
I would name each course exactly like you named the classes in your questions. That way the courses stay together as a series for catalog searching.