You must set kit mode before attempting to change any kit items. We'll set it to 'multi'.

direct 1 64 58 0

Kit item 0 is always enabled, although you can mute it and enable/disable the individual engines.

To be clear though, we'll enable kit item 4 and work with that. For kit controls we set 'insert' to 32. This means we also need to set the intermediate 'engine' value to 255 for some controls.

direct 1 64 8 0 4 255 32

And set its minimum note.

direct 56 64 16 0 4 255 32

Then enable the subsynth engine.

direct 1 64 8 0 4 1 32

And now change its volume.

direct 40 64 0 0 4 1

Note:
    You only use 32 for the kit item commands, not the engine internal commands.
