there are newer versions of sawnds, check the "on-topic" board and you'll see the sawnds topic:P
and just open the brstm's in brawlbox and extract the wave files from it.
so you just have to:
open the brstm in brawlbox
While in brawlbox, rightclick te brstm
click extract
use the wave file that is extracted from it:P
then, put your brsar+your sound (a .wave file) in the same folder as sawnds
open up sawnds
then put in all the values
and click on convert & insert