Unfortunately, you're right. I just checked the DVD out with DVD Shrink and there is no subtitle option for the English version. I wonder if it would be possible to re-assemble the film using the elements on the DVD. I assume that it would be possible to use the Italian print (which does have removable subtitles, if I am not mistaken) with the English soundtrack for most of the film, but since the English film contains material that is not in the other editions, portions of the film would still be subtitled. Still, at least for me, it would be better than having subtitles throughout the film.
Next question: Does anybody know what software can be used to extract and edit the video files from the DVD without a loss in quality?