PHP, RSS and byte order mark

I’m having some problems with my PHP script for generating an RSS feed.
It validates fine using and most aggregators accept it fine.
But MXNA is saying that “Your feed has the tag “<feff>” at the beginning,
before the XML prolog, which is breaking our parser”.

Researching a bit on the subject it seems to me like the issue would be related to the unicode byte order mark.
Notepad apparently adds a BOM when you save a file as utf-8, but PHP, Java and many parsers will choke on an XML file if it has a BOM before the prolog.
I have now resaved the file as “UTF-8 cookie” with SciTE, which I hope will resolve the issue.

But I like to make 100% sure that my file is starting with “<?xml…”, and have no crap before that.
Opening the feed.php in the browser and saving it to disk and to inspect it with a hex editor does not display anything before the prolog, even with the version I saved from notepad.

So…how can I view the raw output of my PHP script in the same way as a parser would do?
And is there anyone who had similar issues with feed aggregators?