How to view wmv subtitles in vlc player using Expression encoder

How to view wmv subtitles in vlc player using Expression encoder

I am using Expression encoder to add subtitles in an video in windows
forms application.
TimeSpan midpoint = new TimeSpan(0, 0, 0, temp);
mergedVideo.ScriptCommands.Add(new
Microsoft.Expression.Encoder.ScriptCommand(midpoint, "caption",
DataLogFiles[j]));
The captions I am adding here are seen fine on Windows Media Player. But I
cannot see these captions on the video in VLC player. Do I need to do
something else for this ? If the question is not clear please comment, I
will add some more code or explanation