FB:
I am not at all familiar with Cubase, but I suspect all sequencing software works pretty much the same. Each channel has to have a bank select and patch select MIDI command, delivered by the sequencing program, which sets the JV-1010 channels to the correct bank and patch at the beginning of the sequence. My software (Noteworthy Composer) allows me to set this as a part of the channel definitions for each staff, and I suspect Cubase isn't any different (being it's about 10 times more expensive, I should think so!).
If you are having a hard time finding these settings in Cubase, the following might help. The MIDI command for channel messages begins "Bn" Hex, where "n" is the channel number (0-F hex, 0-15 decimal). Bank select MSB (Controller "O") is between 80-84 decimal, LSB (Controller "32") is between 1-8, for the JV. Patch select is then between 1 and 128 decimal.
For example, the PowerGrand piano in the Preset A group on your JV would have a bank select MSB of 81, LSB of 1, and patch select of 6. The "Studio Module" you downloaded probably just gives name associations with the patch select numbers (instead of choosing "6" you can pick "PowerGrand" out of a list), but the bank selects have to also be set somewhere.
It is supposedly possible to set up your own bank of patches on the JV which would make it possible to select that bank on the JV panel, and bypass the bank select on your software, but seems like more work.
Hope this helps!
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"The problem with the world is that the ignorant are cock-sure, whereas the intelligent are full of doubt." - Bertrand Russell