Perhaps somebody can correct me if I'm wrong, but I'm starting to suspect the instruction to hit [MIDI] + [TRACK X] (where X=the track number) to sample from another track does not apply if your Track sample slot is set to the Recorder buffer of the other track, and the other track is a Pickup Machine track.
An accident that I had to today, which led to discovering a panning trick:
As usual, I had Track 2 assigned to a slave Pickup Machine, with preamped viola plugged into Input A. I'd left "INAB" in Recording 2 Setup 1 set to "A B". Also as usual, I had Track 4 assigned to a Flex Machine with the Sample Slot set to Recorder 2 (Track 2's recorder buffer). I heard a stereo image coming out of Track 2, but when Track 4 played the slices from Track 2's recorder, the audio was all coming from the left side! I went back to Track 2, set INAB to A , then overdubbed some more onto Track 2. Then Track 4 started playing slices that were panned to the center - all the slices that were taken from the audio I'd just recorded into Track 2 with the A setting for INAB. Now I was hearing audio that was bouncing between left and center. I doubt I'll use this panning trick today, but if I had something else plugged into Input B, maybe it'll be useful.
Another question that came up during the previous study/practice session was "How do I know if my Flex Machine Track really sampled everything from the recorder buffer, and not just the first 2 seconds?". I found the answer in Tarekith's video tutorial:
http://www.youtube.com/watch?v=QJ1kMQKt_rYThe answer:
Enter Audio Editor (eg. double-clicking the button for the Track)
Go to Trim menu
Hold down [FUNCTION]+[Enter/Yes] to listen to the sample.
For today's session, I worked with 32 slices instead of the usual 8.