Seller financing Question

[Sarah Gwiazdowski]

We are working with an eager seller to take advantage of his 3.9% interest rate.  Specifically in New York State, How strong is a land contract?  Will a land contract transaction trigger the bank to foreclose (or require the loan to be paid in full)?  We plan to keep the current mortgage in place and pay it down on behalf of the seller for 7 years, and balloon on year 7.  During this time period, title will stay in sellers name.  We spoke with a lawyer and they were not advising the idea.  Does the lawyer just not want to work a land contract deal? or is it simply too risky?