Need advise on how to proceed with Non MLS short sale

[Des Shei]

Alright, i have a few deals in the pipe line. but this deal fell in my lap last week. it's a short sale and currently is off market. The seller had a VERY LOUSY agent before that put no effort to try and sell the house. I've tentatively agreed on a price with the seller and disclosed to her that i'm a R.E agent as well. My title company found out there's a first mortage, a second mtg from FHA for downpayment assistance and a very small sewer tax lien. Seller has an attorney she'll be using to negotiate the short sale. Now do you folks recommend that i have another agent list the property with and I go in with my contract with the price i agreed with seller? or proceed outside of MLS? Any due diligience and/or advise/criticism of moving forward either way. I plan on putting the offer in tomorrow unless most recommend i have someone in my office list it for the seller and follow through that way.. Thanks in advance.