I believe the extended DVDs lack english subs for foreign languages.
Btw, I think that technically there is a difference between the Director's Cut and the Trilogy.
The DC being the original full length single film and the Trilogy being a re-cut with a different run time and split into 3 films.
Which version of the extended film will you be doing? Are you proposing reconstructing the Director's Cut?
Btw, I've seen the deleted scenes from the DVD, they're kind of crappy. Mostly the scrap film from before and after they yelled cut. Some people mumbling to each other, and the occasionally laugh ruining a take.
Edit: Has the U.S short version ever been on DVD or will this be reconstructed from the Trilogy footage?