If you press the Style Page button TWICE, you get to a nice screen with each Style Part's Volume, Pan, Reverb and Chorus, and a pretty little icon of the Tone type at the top. If you press on the icon, it mutes that sound. Now if you save the Performance, those mutes get saved.

Does the E60 have the D-Beam, too? One of the options for the D-Beam is to mute the ACC Parts (but not Bass and Drums). So you could save the Performance with the ACC mutes on, leave the D-Beam active, and you can now switch the ACC Parts back on any time you want them (and mute them again, quickly).

The REALLY cool thing is, you can STILL mute out ACC Part icons, and have that sound not play at all, but use the D-Beam to toggle on and off the other sounds. It isn't an 'all or nothing' affair.

There's a lot of power under the hood of those things...