In my experience, final negotiations are done after the job offer. Come for the interview - what have you go to lose - and when they offer you the job, state your minimum salary expectation. If they are flying you out for the interview you are at a level where they will be willing to meet your requirements. If not, that tells you a lot. And you will be interviewing with someone other than an HR person. That may make a difference in what story you get. HR is not authorized to make salary offers at your level.
Mandi