Oh well. I was taking my time to find the technically "right" blogging software for my site. Very helpful was this comparison site: http://unblogbar.com/software/. In the end, after one hour of selecting candidates, the outcome was Serendipity. Overall I seem to like it, but the power needed to integrate it into an exisisting website is quite big, and many blogging packages try to force you to do it the other way (integrate your site into the blog). Serendipity has a nice feature called embed, which can be used to capture the complete html output using PHP's output buffering. This has worked well for me right now, although it does not give you the possibility to change the content of that output (although some parts can be hidden with CSS).
Anyway, today I am feeling sick, maybe because of not sleeping enough the whole week. The upcoming weekend probably will not really help with that though ...