On the PC3's, program number 388 is called "LH Timp Roll Orch".
With a name like that, you'd think that the timpani would roll.
I can't get it to, though. Maybe you'll figure it out - I've attached it.

The K2000's have various timpani programs, and the documentation says that the sustain pedal enables a key-up layer for rolls. That just means that you get a drum strike on key down and key up, making it easier to do our own rolls. It should be easy to do the same with the PC3, Forte, Artis, ...

Or maybe get the arpeggiator to rumble for you if you have it?

Good luck!