I understand this is an old post but I have had the same issues with the 4.11 driver not seeing emulated GUS. However after finding some other info this is a known issue with this version and finding a copy of the 3.11 drivers from the web archive fixed this issue mostly.
With the 3.11 drivers, it does detect the GUS but wont finish configuration for sound blaster emulation. If you choose to continue with the install, and ignore errors it completes. I was able to get mididemo.bat playing from IBM's PC dos with this autoexec.bat: @SET ULTRASND=240,7,7,7,7 @SET ULTRADIR=C:\ULTRASND C:\ULTRASND\ULTRINIT.EXE So it seems GUS is working except Soundblaster emulation is not working, but you can use sb16 and adlib with GUS and this does work in apps that support both cards.
