The subtitles are NOT a part of the video stream, they are encoded as a separate subpicture stream.
Also, SubRip needs to work with VOB files, so you have to rip the DVD in DVDDecrypter's FILE mode also !!!
If you only use the video and audio streams in Womble, you will of course NOT see the subtitles.
One possible solution : start Subrip, use it to open the main movie's IFO file (located in the directory with the VOB files )and let SubRip create its' index files. You should see a window with a pull-down menu containing the list of available subpicture streams. Choose english - forced. Then click on the start button to start the action. SubRip will go through the VOB file(s) and search for a subtitle in the selected stream. When it finds some subtitle, it asks you, what letter is it . When the process finishes save the text file in srt format.
Now you have a text subtitle file in srt format synched with the ORIGINAL video. That means if you do some edits in Womble, you have to correct the timings in the srt file. I don't know if Womble supports straight text subtitles, but if not, you have to use some subtitle editor (like Subtitle WOrkshop - free) to do the same "edits".
When you have the correctly synchronized the text subtitle to your video file, you can use your favorite DVD authoring applicaion for creating the new DVD. But please keep in mind, that you can not use text subtitles on a DVD, you have to convert the text file (srt) to a subpicture stream file (sup). This can be done either in DVDLabPro in the authoring phase or in many freeware applications, like Subtitle Studio or DVDSupTools.