I have handled a similar situation involving a property transfer in Malta. I would suggest contacting the Ecuadorian Consulate to determine the necessary procedure. You may be able to have the form drawn up by a local attorney and certified by the Consulate. That is what was done in our situation.
I would just add that you are likely going to need to find out the wording of the POA from your attorney in Ecuador, to meet the requirements of Ecuadoran law.
The Consulate does have information on its webpage. (Link below). Good luck.