Here we go, a very simple code thanks to the contribution of another user.

The code here talks to the Beat707 Software so it knows if it should enter USB mode or not. But this can be removed for anybody needs. ;-)
But there's a problem to which I don't know how to fix: timing. If you use a small buffer (low latency) there's no problem, but if you try 1 second buffer the problem is very easy to spot, and even at low latencies you can notice the drifts. If anyone has a solution, we would love to hear.
http://www.beat707.com/downloads/Beat707_USB2MIDI_Source.zip(requires the JUCE framework from
http://www.rawmaterialsoftware.com)
http://www.beat707.com/downloads/Beat707_USB2MIDI_VST.zip(Windows 32 bits only)