You might also want to check the D4 for a setting called "gate time", or something like it. Don't have mine at hand right now, but I know my Roland SPD-11 percussion controller has that parameter. It sets how long each trigger lasts.
On the EMU, one quick fix might be to just go to the preset and give all the drum sounds a long release time. I also like to add a tiny amount of velocity->pitch mapping for a less robotic sound. And an even tinier amount of velocity->attack so that soft hits have a duller start. If you spend some time tweaking, guess what: it still won't sound like the real thing!
But at least it can sound less like the Nintendo Band. Sometimes.