I just though I'd have read something about "Windows Live Writer"-support of the BlogEngine. And I was right - I tried it and: it just worked... :-D
At first I had to think about how to configure it the right way, but it's really enough to just enter the address of the blog (and the login information). If you do so, the live writer gets all the information it needs automatically.
One click on "Publish" or "Veröffentlichen" (depending on which pc I'm just using) and the newest entry appears.
The thing I like most is: The Live-Writer skales all the images before uploading ... The only thing I'd now wish for the writer is that it could edit the entries. (Dude - it would be great if there'd be a little microsoft man that would just pass this blog at the moment :-D).
Appendix: Very interesting (and I've tested it several times): If I'm using the Live-Writer, a writing "Tags:" appears directly below the entry ... this one disappears, if you save the entry (doesn't care if you changed anything) again.