Convert indicator to EA for backtesting, with custom expiry time for binary option

 
Let's say I have build a custom indicator for binary option, it gives buy sell alerts. I need to know what is the best settings for my indicator to archive the highest win rate. Because I can't backtest indicator in Mt4, so I need to convert it to EA.

I think it is not difficult to convert my indicator to ea, because it gives buy sell alert already.

If I want custom expiry time in the ea, for example: 5 minutes (300 seconds) after alert has been given, then exit the trade. So that I can know my winning percentage in the backtest report? Is it possible?
 
Download latest beta (build 810). It has option for indicator testing.