To turn off parts in performance mode, you'll have to send sysex messages to the JV1010.
Look the supplemental notes at Roland site:
http://www.rolandus.com/SUPPORT/DOCS/SUPNOTES/JVCHANEL.HTM The sysex messages for JV1080, XP50 and XP80 works with all JV/XP synths, including the 1010.
Mgomes