For those wishing to separate drums, one technique i have been experimenting with is making copies of the clip i want to try and create midi from and using various filter methods to isolate the element of the kit. Example, I take one copy of drum break and label it "Kick Copy" . I apply a low pass filter and R-mix to that track to isolate the kick as much as possible. When using R-mix for something like this, don't get to concerned if your kick loses some of it's fatness. The goal is isolation rather than sound quality. Once you have the clip stripped of everything aside from the kick as best as you can, bounce the clip. Convert that to a midi clip using the method described by OP. repeat this process for snares and high hats. Other elements of the kit will be harder to isolate, so needless to say this method works best for small percussion kits like a three piece jazz kit.