PROAS.EXE (version 3.25) will accept an additional option that specifies the "bus 
delay" to apply when the card is accessed: the "L:#" option.

     device=c:\mvsound.sys ...   L:4
     proas L:15

The default in the driver is "L:1", and can range from 0 to 15.  The procedure to 
test the effect this has is to run PAS and watch it fail.  Then,  from the 
command line, execute PROAS with differing "L:#" parameters,  running PAS to 
check if it fails.

Hopefully, a value will be found that allows the card to operate.  When this  value 
is determined, then include the "L:#" parameter on the MVSOUND.SYS line in 
CONFIG.SYS.