Buy property after development agreement

We have appointed developer (privet ltd company)by registered development agreement on our land. Developer developed and sold 60% units. As per our term in development agreement we are not giving possession of our land but permit And enter developer for development. Developer allow to collect fund on behalf of us and developer has to pay our part from collection of fund. Now 40% units are ready or some near to ready. Due to slow down in market rest units are difficult to sell at present day. So we discuss and conclude between developer and land owner that all remain units are going to take over by land owner by paying development charges to developer. We both are agree about it. Now my question 1)How can I take over super structure? 2)What I can do so I not need to pay Stamp duty because I am buying super structure for sell in future. 3) what I have to do so in future I can directly sell and collect amount in my account and I can also albke to go for registry because at present I am owner of land and super structure is buying by me. Please suggest me earliest I am Kalpesh Patel and my contact no is 9687699572 Whose answer is selected from forum we will appoint that CA for our next project accounting work in Ahmedabad.