exporting Subtitles for Dvd

I am looking to have dvds done of a documentary feature I made and I need a version with spanish subtitles. I have two versions of the film as two separate sequences in the premiere pro project-the main English language one and a spanish subtitled version.

In the main English version/sequence there are subtitles in English for 10/15 minutes of the film (which is spanish) the rest of the film is English audio (without subs). The introductory titles (for interviewees etc) are in English.

In the spanish sequence, I have all the titles in Spanish and 10/15 mins of English subs have been deleted (in other words, the majority of the speech is subtitled in spanish at the bottom of the screen). Most all other titles have been translated into Spanish too (including introductory, film title etc).

The guy in the dvd company said they use

DVD Architect pro 6.0 will support:

DVD Architect Subtitle Script (*.SUB), DVD Studio Pro Subtitle (*.TXT), Vegas Region List (*.TXT), Text File (*.TXT)

DVD Studio Pro 4.2.2 will support:

STL, SON, TXT, SCR

What is my best option for exporting the subs? How do I go about it? Have I done the right thing in translating all titles into spanish (translation of English as well as interviewee info etc.) for the Spanish version? Please bear with me, this is the last step in a long process and its been surprisingly complicated! thanks a mil,

Charles