I have put a new version of the xste subtitle editor on my site,
http://www.home.zonnet.nl/panteltje/subtitles/

This version has included in it also submux, subtitle multiplexer
modified to enable also CVD output.
(So different from the version at vcdimager site contributions that has CVD disabled).

xste can produce a variety of output formats.
It is intended to subtitle longer productions, with simple subtitles in BW.
For more advanced picture stuff see 'filter_subtitler' on the same site.
Have fun.
Regards
Jan