I have used the google sitemap generator and it works well. One note though, this week I added a page with the WU historical data, then I went to make a new sitemap. The generator wanted to map over 500 pages. I think it was trying to get all the info from WU, so I just manually added a WX13.php (the history page) to my existing sitemp.
Niko,
I think a site needs to have many pages that can be “categorized” in order to have the sitelinks as you showed.
Google has not generated any sitelinks for your site. Sitelinks are completely automated, and we show them only if we think they’ll be useful to the user.