Yes, that's a very good question and a very difficult question.
In terms of what I think would actually achieve a lasting peace, I'll give you something from my personal experience spending two years living in the country from 2006 to 2008, when I was doing research for my Ph.D. dissertation, spending time in school and literally sitting in history, civics and constitution classes. This is on the Azerbaijani side.
You have the problem now, as you have in any place in the world, where you have two populations that have learned to “other” the other. Without undoing that, which takes human-to-human contact, you're not going to achieve lasting peace. If you're going to have people coming back and living together, obviously first you have to have security rights guaranteed, so that nothing is going to happen. Second, you have to get people to want to trust one another again.
Yes, the first step will be delimiting the borders. Second is creating security, but third, you have to have programs in place like exchanges between young people, getting them to trust one another. I truly believe that's what you're going to have to do to achieve lasting peace.