Hi, Gav -

The WK-3700 (actually the WK-3xxx series) all have software that allows you to create your own patterns. You'll also need to use a MIDI sequencer program (I use PGMusic's PowerTracks). With the sequencer program, you create your patterns in the key of C, including parts for intros, rhythms, variations, and endings. You can import a created MIDI file into the pattern editor and use it to generate a pattern you can load into your keyboard (into one of the user slots). The manual goes into detail about how to do this. It's not a difficult process once you try it once or twice, but will take a little bit of time to create a pleasing pattern. Check out the software user manual under the heading "Rhythm Converter".

Hope this helps.

- John