there is no way to do this with bsplayer ...
bsplayer can only handle his own ini files ... where u can define subtitle files and more ..
u can use virtualdub to create videos with permanent subtitles .. but this requires re-compress and u loss quality ..
there are a new container format ... matroska ... bsplayer supports matroska with recent build ... u can include subtitle files without recrompress ... but its beta and not all features are currently available
check
http://www.matroska.org for more informations
sry for my bad english .. but i'am tired and want to sleep now :D