Triggering external sound module via MIDI track

[Space Firebird]

Hi, I am trying to trigger my external synth module (Roland U220) with the data recorded in a MIDI track using PT10.

Using an Axiom 25 and Mbox 3, I've managed to set up the Axiom keyboard and record MIDI, via USB.
It is also controlling the U220 (via MIDI in / out on the Axiom 25) and I am able to use it to trigger the synth and hear sound on my Aux track.
I am also able to insert a virtual instrument (Vacuum) on the Aux track and trigger it with the data that is recorded on the MIDI track.

The only thing I can't do is get the recorded MIDI data to trigger the external sound module (but like I mentioned I can trigger the module using the Axiom controller).

I've got both the Axiom 25 and the U220 installed in the MIDI Studio with Axiom 25 directlink selected for in/out.
Input to the MIDI track is "All," output is the U220 on channel 1.
Input on the AUX track is interface>input, the only option that isn't a bus.
"MIDI through" is selected.

Any ideas to help me get this wrapped up?