Sorry for this delayed answer.
Yes, you are right. The alternate toms are mixed to the respective tom sound.This is generating sound variations on every hit on a tom. But I discovered an error in the delivered preset drum sets. The alternate tom sounds are not played if the respective volume level has a negative value (like in the presets). Rise the volume levels to values between 0.100 and 0.200 (or higher) for a correct working of the alternate tom sounds.
I will fix this in my next program update (v1.4). Also I will deliver an english manual and some new features like virtual,"velocity sensitive" pads to trigger the respective sounds per mouse click. Also there will be an new drumslot named "Pads" wich will provide this virtual drum pads to control all the drumset and to give a visual feedback to the drummer.