Hi Oz,
You can also change the tempo using the 'Setup' page of the 'MIDI Multi Recording' display (press [RECORDING] > MIDI [Multi Recording]). You may find that this way is the easiest too.
The process is described in the section 'Recording Panel Setups to a Song' on page 73 of the Genos Owner's Manual.
If you change the tempo of the song using the panel buttons, the new tempo will be included in the song if you have the 'Tempo' box checked on the Setup page and you press 'Execute'.
Finally 'Close' the Setup page and save the song to keep the new tempo.
Regards
Ian