NOT sure if this is a primary res or investment, BUT I would HIGHLY recommend talking to a CPA or CFP before moving forward.
Hope this helps! Stay in touch and let us know how it tuns out for you.
It's interesting to see that everyone is assuming that you want to roll a positive difference into the new property, but I'm guessing that you are asking about being able to more the negative difference into a new property. It sounds like an honorable idea, but I think it would only be considered if you are using the same lender. if you do not want to walk away from your debts, then perhaps just sign a note to repay would be easier.
As part of the short sale, you will not receive any money, as stated below by other Realtors. The bank will eat the difference of what you owe on the mortgage and what you get for the sale of the property. They will pay the Brokerage fees and will even pay the movers. Bottom line on the HUD, you get nothing.
If the home is a primary residence, you will not have to pay taxes on the shortcomings up to $2 million. That federal law HR? I don't have the number in front of me at the moment. You can email me for it, if you wish and see for yourself. And, your credit is not nearly as affected as it would be if the bank repossesses on a foreclosure. You can qualify for FHA immediately after a short sale.
Consult with a local FL attorney who specializes in short sales to be sure, as this is what I was taught at a short sales seminar in NJ.
If you qualify for a short sale, you are supposed to be insolvent (meaning unable to pay your bills). In most cases that means you will not qualify for financing a new purchase for two years. So how do you plan to purchase the new home?
Also, you might be able to negotiate a promissory note for the shortage. Depending upon the amount of the note and how it is negotiated might determine the impact on your credit score.