Turning up the volume may not do the job. You could try changing the drum kit to some other one that will off more "bang". If it the Standard Kit try the Power Kit. If it the Dance Kit try the the Analog Kit or T-9 Kit or another.
You can also edit drum notes in Style Creator, but I use the style editing software called StyleMagic because it is a lot easier and you have more access to to various individual drum note parameters like Filter, Resonance, Fine Tune, Note Velocity, AEG Attack and Decay. Since Drum note editing is supported in the SInt (initialization measure) only, that means your drum edits will apply to all style Parts... which is what you probably want to do anyway.