When I checked it shortly before the site reset, there were no replies anyway.
I do not have bluray and can't check, but some research shows you need to demux the subs into a .sup file. A tool named tsMuxeR looks like it will work.
http://www.videohelp.com/tools/tsMuxeR (and it supports Windows/Mac/Linux which is good).
To use tools like subrip (to get an .srt) you need to convert the .sup to .sub/.idx using a tool such as BDSup2Sub
http://www.videohelp.com/tools/BDSup2Sub
I put a thread up on subrip in the help forum a while back, once you get to that point.
They may well be other better tools, but this is what I found, maybe it will help. If you can follow up with more specific questions then I can research more when I have time. My experience with doing this stuff with DVDs is that there are often twists you need to figure out or search for solutions for.