seller financing with an existing mortgage

[Kevin Hart]

hey BP'ers, 

i have an off-market deal that i am trying to buy. I'm trying to avoid spending all my cash on a down payment. the seller would be interested in seller financing but he still has a mortgage on the property. the sellers owes about 130k, selling property for 265k. any creative ideas on how to structure seller financing when there is a mortgage present? 

im not sure whats possible without having the "due on sale" clause impacted. thoughts?