Is it possible that the file being executed is not the one you think is being executed? Have you put in obvious syntax errors, echos, or exits to confirm that your changes are being made in the right place?
I only ask because most of the time that I run into a really weird problem, it's either in my data and not my code, or I'm looking in the wrong place. If you're editing the file and nothing is changing, then it's possible the web server is not using the file that you're editing.
Fortunately with this, the only file I should have to worry about is rss.php.
You're correct in that I don't really know the state of the text when rss.php gets it. Is it html or entity-encoded?
Part of what rss.php does is run the data through a series of conversions in order to get the data into an RSS-compatible state.
With this issue, specifically, the amlaut could be in one of three forms when rss.php sees it, and I want it to end up in a fourth form.
So, what I did in my last effort, which hasn't been responded to yet, is convert the data three different ways.
Another problem is that I use the "htmlspecialchars()" function a couple of times, and I'm not entirely sure I put my changes in the proper place, EXCEPT that the dashes problem went away.
If that part worked, then I'm assuming (which I don't like doing) that in my previous attempt, my code to convert the amlaut was incorrect, which is why I've now included code to convert the amlaut from its other two possible forms.
If the last copy of rss.php I sent doesn't fix the issue, I'm going to have to set up phpBB and do this "right".
Currently, rss.php has very little error-handling of its own.