http://bugs.winehq.org/show_bug.cgi?id=28415
--- Comment #1 from Daniel Bielak dbmmbr@gmail.com 2011-09-18 19:19:17 CDT --- CORRECTION:
In previous versions of Wine that I've used, including recent versions of Wine, VSTHost did recognize all of the available OS X MIDI ports. I don't know whether or not VSTHost, in Wine 1.3.27, did recognize any MIDI ports. I don't know in which recent version of Wine VSTHost began to not recognize any MIDI ports.