Attempting to sell short so you can upgrade to a larger property is not justification. In addition, lack of cash reserves will also serve as justification. It depends on the lender and how well you can negotiate. If you have a Freddie Mac loan, Freddie Mac will probably want you to contribute to the short sale, get your agent to reduce brokerage fees, and get the buyer to take the property with the termites. Some lenders will just ignore you.
Packaging is very important.
It seems if I can save the brokerage fee that the lender would net more and be more inclined to accept any offers that come in. You are correct. If you're loan is current, you may be able to get a qualified buyer yourself. If your loan is delinquent, or in default, you don't have time to play around getting your home sold. You need as much exposure as possible.