PS. This is recording for a song not live.
If you are playing a song, and want a bar of silence, the options are:
1. Hit the Stop button when you want silence to start; hit Start when you want the rhythm to start back up.
2. Hit the Sync Start button (when the style is running, this will stop it); play a chord in the left hand to start the rhythm
3. Turn the style volume down to 0 (using the slider) for the period of time you want silence
If you just want the accompaniment to stop (but the drums to continue), hitting Break will often do that (but will almost never give you a bar of silence).
If you use Fingered mode, pressing any 3 adjacent keys will stop the accompaniment (but not the rhythm).
If you already have the song recorded (ie, have a midi file), you can insert a bar of silence with almost any midi editing software.
Hope this helps,