Actually, I just tried again several options. In my experience, the biggest problem with using vsig lies in dealing with the serial connection from a Windows inside MacOSX.
So, I tried again the old VsigX. Actually it seems to work quite well on my system (OSX 10.6.7)
What I did:
-install the latest drivers for the Keyspan USB-serial interface (model USA-19HS) (drivers available on http://www.tripplite.com/en/support/downloads/index.cfm?txtArchive=0&txtLang=&txtOS=
-finish the installation of the USB-serial interface according to the Keyspan manual
-start VSIGX
-in Preferences… -> Connection -> enable Serial and choose the correct device, in my case something like cu.KeySerial1 (and maybe check all options are the same on the unit and in the Preferences: Baud rate, etc.)
-menu MIDI -> get sigDbase (YOU HAVE TO DO THAT before opening your patches, to have the correct data for your unit) … be patient… check the unit is sending something (look at its screen)… when it's done, you will have to give a location and name for the database…
-now, you should be able to use for instance MIDI -> Get Patch
Show More...VsigX is quite old (version 1.9beta released November 2006). But vsig is quite old too, and still in beta too (version 2.4.9beta released October 2007).
Bottomline is: try VsigX again. That might be your best bet. Ask questions here if you don't succeed.
All best.