Which Florida Bank/Lender allows owner finance in 2nd position ?

[Christian Podedworny]

 I am in the process of negotiating the sale of 2 potential properties with a seller. He has two quadplexes that are adjacent to my Quadplex in Tampa which he looks to sell for $200,000 each ($50,000 per unit). The total price would be $400,000 (8 units)  after the negotiation. 

He told me he is willing to hold 10 % of the down payment as the owner finance portion for maybe 3-4 years and then there would be a balloon at the exit. This is how I seek to structure the financing :

Purchase price : $400,000    

Down payment: 15%   $60,000

Owner finance (2nd position) :            $40,000

 The issue I face is the banks are reluctant to structure a deal this way and they say I need 25% of the down payment which I do not have. I understand there are other angles to pull with owner financing but the seller is fixated on getting the deal done this way. 

  I was told there are portfolio lenders and community banks which would underwrite this type of loan but I live in New York and I do not have any connections with local lenders.