Ask how much other people in the position make in bonuses and other compensation. Sometimes the whole package can beat the salary at the old place.
For instance, my husband took a job making almost $30k less in salary than he was making at his other job (same field), but he knew he could make more with the profit share that they were offering. Further, he found the idea that he could control the amount of money he made by working harder and smarter very motivating.
One thing he did that you might try. He told his prospective employer that he wanted to make at least x amount a year, and that the salary reduction would be tough. So, they negotiated a deal for the first profit share cycle, during which he made more than the usual salary, and they guaranteed a certain percentage of the location's profit for that year.
This helped ease our cash flow transition. We relocated for this job, so we arranged our life (mortgage, etc.) so we could live on just the lower salary. It has worked out well, because the profit shares have been twice what his salary was, and therefore about half-again what he was making before. They are like icing on the cake. I get new furniture, vacations and bike stuff every March!
So look at the whole package. If they won't give you the salary, ask for a guaranteed bonus for a period of time to make up for the loss in pay.
Karen