OT: How to translate DocBook documents into different languages

This is off-topic, but maybe some of you are sometimes faced with the 
same problem:

I have a long English Docbook document (440 pages in  printed output) 
that I want to translate to German.

There a two important points for me:

- In the English document, I don't want to type in again all the markup 
which took me so many hours. I want to reuse my precious markup. The 
structure of the target document will be exactly the same.

- I want to use a translation program to produce a first, rough version 
of a (mechanical) translation.

What is a good approach to do this? Can these steps be mixed? Are there 
programs for these kind of jobs? Any experiences? Advices?

Thank you very much in advance,
Joachim

-- 
Joachim Ziegler                       Stuhlsatzenhausweg 85
Max-Planck-Institut für Informatik    66123 Saarbrücken, Germany
Email:           Tel.: (+49) 0681 9325-127