Implement a Indicator in a EA?

Hey Guys,

I know how to get specific data from a indicator in a EA. For example I use iMA to get the current data for the moving average.
But I also want to visualize those data for the user.

So my question is, how can I implement the moving average so that the moving average is appering on the chart?
Also I want to visualize the Supertrend Indicator. Has anyone a idea? - Because in the EA there is no OnStart()-methode or OnCalculate()-methode...

My code for and moving average Indicator:

#property indicator_chart_window
#property indicator_buffers 4
#property indicator_color1 C'240,192,192'
#property indicator_color2 C'192,240,192'
#property indicator_color3 clrRed
#property indicator_color4 clrBlue
#property indicator_width1 5
#property indicator_width2 5
#property indicator_width3 2
#property indicator_width4 2

extern int                  MA1Period=21;
extern ENUM_MA_METHOD       MA1Method=MODE_EMA;
extern ENUM_APPLIED_PRICE   MA1Price =PRICE_CLOSE;
extern int                  MA2Period=50;
extern ENUM_MA_METHOD       MA2Method=MODE_SMA;
extern ENUM_APPLIED_PRICE   MA2Price =PRICE_CLOSE;


double buffer0[];
double buffer1[];
double buffer2[];
double buffer3[];


int OnInit()
{
   SetIndexBuffer(0,buffer0); 
   SetIndexBuffer(1,buffer1); 
   SetIndexBuffer(2,buffer2);
   SetIndexBuffer(3,buffer3);
   SetIndexStyle(0,DRAW_HISTOGRAM);
   SetIndexStyle(1,DRAW_HISTOGRAM);
   return(INIT_SUCCEEDED);
}

int start()
{
   int counted_bars=IndicatorCounted();
   int limit,i;
   
   if(counted_bars<0) return(-1);
   if(counted_bars>0) counted_bars--;
           limit=Bars-counted_bars;

   for(i=limit-1; i>=0; i--)
   {
      buffer0[i] = iMA(NULL,0,MA1Period,0,MA1Method,MA1Price,i);
      buffer1[i] = iMA(NULL,0,MA2Period,0,MA2Method,MA2Price,i);
      buffer2[i] = buffer0[i];
      buffer3[i] = buffer1[i];
   }
   return(0);
}

Thanks!