Sound problem in DOS

[Lunever]

This is a copy of a reply I posted in the DMute section, but since it concerns DM1 rather than DMute, I post it here also.
Problem: I´m using an VIA AC´97 onboard sound (Hardware version 32) with Win98 (Version 04.10.1998 on an Athlon AMD1 (100x10Mhz).
When I try to start DM1 from Win98 I got all options (VGA/Mouse/Sound Blaster) but after choosing those the task ends complaining that the prog will run only in pure DOS mode.
When I create a link to reboot the prog in pure MS-DOS or better create a batch file with uploading MSMouse.exe first and use it, the prog works fine, but only opts to use PC Speaker sound which works fine (when I use a boot disk instead I can also choose PC Speaker and get a little bit of sound during the intro but then the game begins with the message "No Sound").
The Problem is, that I only ever get sound via the internal PC Speaker with a very low volume and absolutely no sound out of the external speaker.
When I try to install the DOS drivers provided on the VIA site, I always get the error "Please enable Legacy of Sound Blaster in BIOS first", whether it is enabled or not.
There seem to be many users complaining about that very same problem on the VIA forum, but no solution is provided by VIA (only very incompetent suggestions for solution).
I already tried to use the configuration from DM2, but that game or doesn´t work at all on my machine.
Please, can anyone help me or has any clue what to do about it?!? I´d be very grateful for any support!
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