In Step mode, no. You can record it in step mode though, then go into the
Pattern Edit Menu, and scroll to the right really fast to get to Note
Edit, which is basially a List Editor. Make sure you're on the the right
track/channel, then press Enter to view your notes. From here, you can
change the durations (and velocities) for all of you recorded notes. Don't
forget to resave the Pattern when you're done!
rEalm
But is there a way to extend a note when your using step mode and not just
make the stacato.