Best ways to structure deal on Home with mortgage

[Angel Hernandez]

Hello All,

I am running into an issue and would like some clarification if there is anyone that can help. I am coming across some good leads that need rehab work done but some of them have a mortgage. I would like to structure seller financing but I do not have enough of a down payment to cover the existing mortgage and fund the rehab. I do not want to risk running into a Due On Sale clause that may pop up on a seller financing deal with a bank mortgage. What are some strategies that can be utilized to get into the home and pay a monthly payment while I rehab? 

I am thinking a land contract, or some sort of lease option but a lease option may not work do to the extent of the rehab. Is there something that I am not seeing or can this even be done? 

Any and all feedback are welcomed. 

Thanks