strategy tester problem

[persy5]

long gbp = ChartOpen("GBPUSD",PERIOD_M5);
ChartSetInteger(gbp,CHART_MODE,CHART_CANDLES);

Why second line doesn't work on strategy tester and so when I use _Symbol when chart GBPUSD is opened Its don't give me a "GBPUSD"?

How to fix this? 

[Simon Gniadkowski]

persy5:

Why second line doesn't work on strategy tester and so when I use _Symbol when chart GBPUSD is opened Its don't give me a "GBPUSD"?

How to fix this? 

There are many things that don't worth in the Strategy Tester,  maybe this is one more . . .