If you contact Bolsa de Mercadorias e Futuros (or Bovespa, they are working together now), they should indicate a Broker in case your doesn't do it. A long time ago (one of my very first jobs) I used to work at the trading table of Citicorp. Usually options could be done 12 months (forward) abroad and 24 months in Brazil, against dollar. But financial instruments were different then. I'm getting old...

I hope you succeed in offering this plus ("insurance" against flutuation) to your clients.

My personal take is that if someone from abroad choose to buy a property in installments today (for instance, 3 years), may even do some profit with a contract in Reais. But that is a long shot, and I hope no one will knock my door 3 years from now to complain, but in case of a profit, mostly welcome to share with me!