Need help with Creating a Contract with an Owner in Pre-Foreclosure?

[April G]

For a contract for my exclusive rights to work with the owner, what should my contract say? Does anyone have a sample copy for me to go by?
I know that I need a letter to the lender from the owner authorizing me to speak to the lender regarding a short sale. I include Loan # and last 4 digits of SS#. Anything else?
But shouldn't I get a contract between myself and the seller to keep someone else from sweet talking them out of using me? And what should it say?

Thanks!