Check the screen shot to see where to select the default midi note value. While you can't see(because I cropped the shot too much) is that the notes I dropped with the mouse are indeed 16th notes as selected(Grid value is set to 8th notes). Writing drum fills with a mouse is going to be frustrating at best. Using some kind of midi trigger or midi keyboard would allow you to "play in" notes that approach the actual dynamics of a drummer. When I use a trigger pad device(M-Audio Trigger Finger or my current Akai midi keyboard), I configured a bank of trigger pads in pairs(IOW< 2 pads for snare, 2 pads for tom 1, 2 pads for tom 2, 2 pads for tom 3). By using separate pads for left and right fingers(equating to left and right hands of a drummer), I am able to program drum fills that get very close to "real" sounding. If you only have a keyboard, then just pound out with 2 fingers on 2 separate keys to record the note triggers, then drag the notes to the proper notes on the piano roll so you trigger the desired drum sound(s).
Additional points;
1-What VI you use for drum sounds can make a huge difference in the results.
2-Having rudimentary drumming skills makes a lot of difference.
3-if you have no drumming skills, using a drum VI with loops included will improve your results dramatically(EZdrummer and Addictive Drums are 2 reasonably priced plugins that are very easy to use for creating solid drum tracks with no drumming skill)
