Value of one pip can be obtained using
Instrument.getPipScale();.
The code could modified be as follows:
double pip = myInstrument.getPipValue();
TP = pip * 3;
Also, please consider using askBar prices instead of bidBar, to calculate more accurate stop loss and take profit prices:
engine.submitOrder("Order" + orderNumber, instrument,IEngine.OrderCommand.SELL, lot, 0, 1, askBar.getClose() + SL, askBar.getClose() - TP);
Please, give more details on how do you would like to change the strategy, what is the algorithm?