to dust
question asked and answered not far from here...
http://forum.bsplayer.org/viewtopic.php?t=2648
or did you see that and were not satisfied with the answer ?
[I did not read the linked tutorials thoroughly, but I don't know of any other way to add subtitles permanently to a movie]
to HackerWerger
Right click on the controls [or right click on the movie and select 'other menu']; there is a
save as... item in this menu
I'd say it's quite pointless when you already have the movie file on your HD, but I think it can prove useful when you're playing a file from an internet source for instance