although if i remember correctly… while it is possible to trigger samples on a channel in slot mode using an external midi keyboard, it is not possible to record the playing of different midi notes onto the track, so it doesn’t quite work for recording.
the Midi tracks do however record incoming note pitch, velocity and length from an external midi keyboard, realtime. That doesn’t really help unless you are willing to connect the Midi Out to the the Midi In … i’ve read it is possible and does work.