What I am going to propose is something I have not seen proposed anywhere, but it will certainly separate you from the other candidates that are competing with you.
As I had indicated in my previous blog titled, "How to best handle the initial phone interview for a job?," you have to change the game and differentiate yourself from others.
Companies really don't know what kind of hire you will turn out to be for at least three months into a job, so you want to reduce their risk by suggesting that you are willing to work for a lower salary for three months and then negotiate the salary.
This gives you an edge since you may not want stay if the job does not meet your expectations and similary you are giving the company an opt out without any repercussions financially or legally.
I would work real hard and then negotiate a salary higher than the one they were going to offer since you have given them a trial period.
This shows that you are thinking out of the box, reducing their risk and is not driven by money, but passion for accomplishment.