Assuming you are asking from the perspective of the tenant, and Wells Fargo is the the lien holder for the owner's property that is being rented, the best option is to shop around for your (the tenant's) own financing. The owner's lien holder really has no say where you obtain financing so long as the purchase contract and terms satisfies their requirements regarding the short sale.
In case you may not be aware, the short sale closing process can take much longer than a property that is not a short sale. In some case, the approval of the purchase (by the lien holder - assuming there is only one) can take up to 8 months and even then, they can change the terms of the purchase (but not your financing.) Make sure you consider the terms of the current lease (expiration and option to extend or go month-to-month) if and when you head down the short sale road. Also, make sure you use an agent with short sale training and/or experience. This will help to avoid further delays and pitfalls.
If you need any help, I have a resident mortgage broker in my office who will be more than happy to answer your questions and offer financing options. Just email or call me if interested
214-728-1650 / email@example.com