Routing USB-only MIDI keyboard using Express XT

[Proton17]

Hi board,

I recently got a used Express XT so that I can patch MIDI inputs and outputs independently of my DAW (using Logic). It's been working great - I installed Clockworks and it's dead easy to route any of the inputs and outputs as desired.

I recently started using a mini keyboard controller (Arturius Minilab) for entering note info, and while it works great it's USB-only (no 5-pin DIN). This is great for compactness and minimizing cable clutter as I don't need a wall wart. However I have not been able to find any way to route the MIDI output of the keyboard (sent over USB obviously) to one of the MIDI outputs of the Express.

I thought that this could also be set up in Apple's Audio MIDI setup, but for some reason I can't hook the output of the Arturia to any inputs on the Express. I can drag from the output but it won't 'stick' to the inputs on the Express.

I've installed the latest Clockworks version from MOTU (1.6 49342) and did install a firmware update. I'm also on the current version of OSX (10.9.4), running on a 15" MacBook Pro Retina.

I'd be very grateful if anyone could suggest a solution (of if it's not possible).

P