Need some direction with a short sale

[Es Lee]

I am a seller trying to attempt a short sale and need some assistance. I have a 4/3 house in Melbourne FL. Owe $300K with Chase trying to do a short sale for $250K. I have a foreign cash buyer. The home is not listed with an agent. I am current on my mortgage. Relocated for a better job opportunity in Nov 2007 to GA. Trying to negotiate for a waived defiency judgement.
Contacted Chase and they said send them a short sale package. How do I put together a winning case based on my hardship situation?