I'm guessing this is a midi channel issue, i.e. your Roland kit is transmitting notes on channel 10, and your software instrument is set to respond only to that channel. When creating new notes with your mouse those will be on channel 1, so Superior Drummer won't sound. In the track inspector, you can set the "MIDI Out Channel" to 10, to have all notes going to the instrument "re-channelized" to 10, then all notes should sound... I don't know Superior Drummer, but it's possible you can set the midi channel in there to "all" or "omni" as an alternative fix.