[vlc] How to make "--sub-fps=<float>" work?

[Richard Ivarson]

Hi,

http://wiki.videolan.org/VLC_command-line_help
says:
=====
--sub-fps=<float> : Frames per second
Override the normal frames per second settings. This will only work with
MicroDVD and SubRIP (SRT) subtitles.
=====

However, I can't make it to work with standard srt subtitles. Is there a way
to make it work?

-Richard