Gst applicable for commission received from foreign principa

Mahesh Pandit (Manager- Accounts & Admin.)   (48 Points)

30 June 2017  
Dear Sir,
 
I run a propreitorhip firm in Delhi through which I provide product promotion and marketing services throughout India to my principal,who is located overseas and does not have any office / establishment in India. Incase of a sale, the Indian customer places an order directly to my foreign principal who ships the goods directly to the Indian customer.I then raise an invoice to my foreign principal in Euros,based on the percentage of the order amount as per our agreement and then my foreign principal pays me the commission in Euros. My firm's name is not mentioned in Indian customer's order nor on the Invoice raised by my foreign principal.My firm is also not invloved in clearing these goods through the Indian customs. As of now I understand that I am required to pay service tax @ 15 %  for above activity, However after July 1, after GST is established :
1.) For above activity do I need to pay any GST ?
2)Is it that I need to pay GST only if my commission income crosses the threshold limit of Rs 20 lakhs in a financial year ?
3.) Should I register for GST only after my commission income crosses Rs.20 lakhs ?
4.) Should I use my invoice,which I raise to my foreign principal,for GST purpose ?
6.) In the next year,if my commission income falls below Rs.20 lakhs what do I do ?
Wram regards,
Mahesh