Francesco Z,
Greetings and parameters.

I believe you can accomplish muting midi channels on your JV1010. This is only something I have seen in the cd-rom reference manual that came with my unit. It is not something that I have tested out myself, and I hope that you have a copy of the cd-rom.

In the parameter reference section, look for chapter 2, section 2: functions of performance parameters. In that section look for "making midi settings for a part". This should explain the actual function.

Then, go back to the performance parameters section of the cd-rom to actualy change the parameters under the "midi group" section.

Hope it works,
Key Juice