You may have already read the first part of ways to prove that, while "overqualified"–or, rather, "highly qualified," as I like to call it–you are still the best candidate for the position.
1. Ask about their concerns. If a hiring manager seems hesitant or repeatedly brings up your past experience, ask what his or her concerns about you might be. You may have explained how your skills and experience will benefit you in the position, how you'll be challenged, and told them about your goals for the position until you're blue in the face. But the hiring manager might still seem reluctant.
By asking, you're again showing you are proud of your achievements and you care and want to hear what he or she thinks. It's actually a great way to build on the relationship you have with the hiring manager, and it provides you with an opportunity to mitigate any perceived risks of hiring you.
2. Wear your passion on your sleeve. You have to squash the hiring manager's fears that you just need a job and are going after anything. You have to help the interviewer understand why your business experience is relevant–but you also need to let him or her see you have passion for the job.