Ensoniq Creative AudioPCI sound card autoexec.bat woes

The driver package for this card installs an unwanted legacy audio
device inside Device Manager. It also adds a "SET BLASTER" line
inside autoexec.bat, which "cancels out" my own SET BLASTER line for
my real SoundBlaster card.

If I remove the unwanted SET BLASTER line, the legacy audio device
simply adds it back in after a reboot.

If I remove the legacy audio device from Device Manager (by removing
it from my specific hardware configuration profile), what happens is
that after any reboot, I find that my own specific SET BLASTER line
gets removed!

Now that the legacy audio device has been removed from my specific
hardware configuration profile, how can I stop it continuing to meddle
with my autoexec.bat file?

Any thoughts gratefully received. Thank you. Best regards, Robert.