Hey Ohm64 and other light-up controllers out here -
I just cobbled together a quick qc patch / plugin that should help you getting the midi out / led feedback you desire. Fairly simple to setup and use.
The first step is setting up your ohm64. I'm not sure how or if its possible to save out ohm64 presets so you will need to set you inputs up exactly like this for it to work:
Next, you need to go here and download this great miditools qc plugin by the folks at Kineme. When you arrive at the site you will see that it is "restricted access". To gain access you must register for the forum - and then under you account settings (My Account at the bottom of the left hand side) check the Beta Tester box. Then the link below will work - a little cumbersome I know... but I don't mind jumping through some hoops for a super helpful plugin.
http://kineme.net/MIDITools20080205beta
I had to put it here /Library/Graphics/Quartz Composer Patches
(if the folder is not there - create one)
Next - download this file:
http://roevy.com/vdmx/o64_mapattack_01a.qtz
Throw this into your VDMX/plugins directory.
This plugin should now appear in your "Plugins" panel in VDMX - Its a series of buttons 1-81 which when activated will activate the lights ohm64. I've already assigned all of these buttons to the ohm in a vdmx project which can be found here:
http://roevy.com/vdmx/ohm64_demo.vdmx
One final note - I've set the midi channel to 5 in the qc patch. Needed to for my setup. By default ohm64 is on omni-mode / merge mode - meaning it will pick up midi out from all channels so probably won't be an issue for you.
Hopefully all of this works for you! or at least helps point you in the right direction for your project!
Nate
PS I am pretty much an amateur at this qc stuff - so if there are any better ways of accomplishing this - let me know!