Use the form SSA, the short sale addendum (revised 11/07). Mark on paragraph B that your 17-day inspection period begins the day you receive the bank’s approval of your offer. That’ll get you 1-3 months extension of your inspection contingency time to shop the market. If your offer is finally accepted by the bank, and you still like the property, you’re in a position to purchase it – go get your inspection and appraisal then.
Paragraph A also puts a limit on how long you are willing to wait to receive the bank’s answer, but you could include that in your standard offer-expiration paragraph.