Nope. Asked a few times but nothing so far. Workarounds are to run two instances of renoise, or drag midi data into a new song, copy the pattern info to the original song.
I just sample stylus as it plays, chop it up and mess with it in Renoise. As of today, midi export from stylus (and similar programs) isn’t really doable in Renoise. Or at least certainly not worth the trouble in my opinion.