Reply to myself...
The problem seems to be in resourcing, since there are quite many devices in the system.
However the "not so easy way to go" solution:
-I built up a separate PC with plenty ISA-slots (Pentium era) and dug up one Sound Blaster Pro for the trick.
This is the way to go for ultimate compatibility, but somehow the face of my wife was worth seeing when "one more of those tin cans" appeared in my "work" room... unique.
Now, if someone would sponsor me a little spare time