actually an even cooler way to use ezdrummer for hit replacement in Reaper..is to use the reagate plug in...
you add an instance of ezdrummer to say your kick drum track... set regate to trigger midi note 36, channel one( midi triggering is built right in Reagate!)... and wala!! Instant dumagog style kick drum replacement with the Reagates multitude of fine tuned gating functions ( low pass , high pass, pregate, hold, etc) it works awesome.... and when you have it dialed in , just print the effects to a new track and you can save cpu power!