[amibroker] Help with Oscilator Color change

[Larry M Powell]

I would like the following to be Green when positive and Red when 
negative
 
priceOscillator = EMA(C, 39) - EMA(C, 189) ;
Plot(priceOscillator,"",colorBlue,4);
Plot(0,"",colorBlack,4);
Title= Name() + " " + "[PrOsc 39,189= " +
WriteVal(priceOscillator,4.2) + "";

 
Thanks,

Larry M Powell