Power of Attorney from property purchase from outside India.

I am currently outside of India. I need to create a PoA to allow my brother to buy a property in Delhi on my behalf (including signing affidavit, conveyance deed etc). I will get PoA & my signature apostille from Indian embassy. Please advise me on following 1. Do we need to register PoA at sub-registrar office in Delhi? If yes, how to pay stamp duty and how much to pay stamp duty for this PoA. 2. Is there template of PoA for this purpose? 3. How can I pay stamp duty of an apostilled affidavit? i have an that affidavit was expected to be on Rs 10 stamp paper. Because I am outside India, I got affidavit apostilled from Indian embassy on A4 paper (with required content). Now, I need to pay stamp duty of Rs 10 How to pay this stamp duty? Is it same as buying e-stamp paper from www.shcilestamp.com? Or is it something else? If you can please help me, with this process and interested in it, please let me know your contact details and fee via email.