Rule #1: You can never get what you want in any negotiation without being willing to walk away... even when it hurts; otherwise you're not negotiating you are simply capitulating.
Rule #2 (and this could easily be swapped with Rule #1) You don't try to negotiate with people who don't Desire what you have. If they don't desire it, then you are simply selling the lowest possible price.
The key to successfully negotiating really is that they Have to DESIRE what you have.
Greedy--well you folks likely poured your heart, soul, and imagination into this. This isn't a hobby, and you're not children, it is how you eat.
And listen: if you have drop your salaries do it in very Small increments during the rest of the negotiation. I'm assuming that they want to talk in 10,000 dollar increments--you Have to drive that conversation by using 1,000 dollar increments. That will set the tone and enable you to lessen the blood loss... unless of course it blows the whole deal up. It might.
GL