1. If you approach banks, they will obviously insist for registered documents
2. If you are funding yourself from your own funds then you wont find problem
3. Issue a public notice informing about the 1st agreement being duly stamped but not registered
4. Then in your agreement for sale, attach a certified true copy of first unregistered agreement. So with your agreement, the first agreement will also come in registration records and public will deemed to have knowledge about it
5. I do not find any provision in the registration act wherein it is stated as to what can be done if one of the parties to the agreement is not available for registration
6. In such cases mostly the remedy lies to approach the civil court and seek a declaration of ownership and direction to registrar to register the document unilaterally without insisting for the party who is not traceable
7. But bear in mind if in future you wish to sell this property and your buyer applies for a bank loan, then again his loan may be refused if the first chain agreement is unregistered
8. If your intention is end perpetual use, then you can take a chance of not seeking a declaration from court. That is you can do away with requiring your seller to seek a declaration and direction from the court as stated above