reverb, delay, and filters.

makes sure you using constant reverbs and delays across them all. once you get it once its not hard to do it again just keep trying. i don't know the EZdrummer interface, but if it allows you to do individual filters on each part of kit you should do that.

I am actually about to add some ambient drums to a song now...
try sending the whole drums to a reverb bus, then compress the shit out of the reverb. It can sound pretty good.