I have been thinking how to get this working, and I came up with the idea to use \part as if it were \chapter, and to put each article in a \chapter. Unfortunately I don't seem to be able to get it right, because the structure that emerges is like this:
I. Introduction (part)
1. Intro-paper number 1 (chapter)
... 1.1 Bla (section)
2. Intro-paper number 2 (chapter)
II. Techniques (part)
3. Techniques-paper number 1 (chapter)
... 3.1 Bla (section)
4. Techniques-paper number 1 (chapter)
While I would like something like this:
1. Introduction (part)
1.1 Intro-paper number 1 (chapter)
... 1.1.1 Bla (section)
1.2. Intro-paper number 2 (chapter)
II. Techniques (part)
2.1. Techniques-paper number 1 (chapter)
... 2.1.1 Bla (section)
2.2. Techniques-paper number 1 (chapter)
The major differences between what I get and what I want are:
- the paper numbers (chapter) are not "resetted" when a new part is started (the numbering continues)
- the papers (chapter) are not numbered using 'sub'-numbers ('1' instead of '1.2')
- the parts (part) are numbered using Roman numerals
Who can help me out? Should I use another approach? Is there a way to get it working anyway? Should I be using Microsoft Word?

Any help is appreciated!