Amibroker: Adding green/red buy/sell vertical lines over price pane

I wrote my first Amibroker formula to find buy and sell points based on a couple of indicators, and I am able to run the optimizer on it, Amibroker is really impressive. For backtesting I'd like to draw a green line at each buy and a red line at each sell, and I can't sort it. Any help would be appreciated.