Borrowing a down payment

[Tobey Porter]

My wife and I have recently started our REI career. We have a couple under our belt and are looking for another. My question is about borrowing the down payment. We have tapped our resources w/out going into our emergency funds as much as we are comfortable.

My in-laws have a HELOC on their primary residence and have offered to let us use that as they have no intention of using it for anything.

Are we allowed to borrow a down payment?  And how would we structure the payments to them?  Obviously, on top of the interest they pay, we would pay them additional interest for the use of their $$.  Has anyone had experience doing this and how did they structure the deal?

Thanks!!