Talk to the lender and point blank ask them (and get the answer in writing). Most are going to report it as a foreclosure. If your 1st mtg is with the same company and it will be paid in full with the sale of the house, you may have some negotiation room.
Also keep in mind that the amount of the loan that is "forgiven" is considered taxable income. There was a bill recently submitted to Congress to change this part of the tax laws, I'm not sure if it was part of the stimulus package that passed or not (you can google it to find out).