If I were you, I would try to have a real conversation with HR and/or the hiring manager. If it's with HR, then ask them about the likelihood of them calling your boss.
The best option would be to have an informational interview with the hiring manager. Can someone arrange an introduction for you? You can't be more than two points of contact away from him/her. Once you are able to talk to a human about your qualifications for the job, THEN you apply via the database. Obviously, I would only do this if you are very interested in the job and think it would be a good fit. If this is the kind of thing your applying to for sh*ts and grins, you should reconsider because of the possibility of them contacting your current employer.