ger -
I actually found that by using an example from one of iwonder's posts that ampersands do indeed work so long as you escape them with &. Something else in your OML is probably doing the damage. The OPML has to be properly formed, the Feed Explorer is very unforgiving and will load the default collection if you have any errors.
I used the following OPML from iwonder from this thread:
<?xml version="1.0" encoding="utf-8"?>
<opml version="2.0">
<head>
<title>Your News</title>
<ownerName>your domain</ownerName>
<ownerEmail>your email</ownerEmail>
<docs>http://www.opml.org/spec2</docs>
</head>
<body>
<outline text="Rueters" type="none" category="Tab">
<outline text="News" type="none" category="Section">
<outline text="Oddly Enough" type="rss" category="Category/@@3000px" xmlUrl="http://feeds.reuters.com/reuters/oddlyEnoughNews?format=xml" />
<outline text="Top Stories" type="rss" category="Category/@@3000px" xmlUrl="http://feeds.reuters.com/reuters/topNews?format=xml" />
<outline text="World News" type="rss" category="Category/@@3000px" xmlUrl="http://feeds.reuters.com/reuters/worldNews" />
</outline>
</outline>
<outline text="Google" type="none" category="Tab">
<outline text="News" type="none" category="Section">
<outline text="Top Stories" type="rss" category="Category/@@3000px" xmlUrl="http://news.google.com/news?ned=us&topic=h&output=rss" />
<outline text="World News" type="rss" category="Category/@@3000px" xmlUrl="http://news.google.com/news?ned=us&topic=w&output=rss" />
<outline text="Sports" type="rss" category="Category/@@3000px" xmlUrl="http://news.google.com/news?ned=us&topic=s&output=rss" />
</outline>
</outline>
<outline text="WizzoDawg" type="none" category="Tab">
<outline text="News" type="none" category="Section">
<outline text="Portal 0" type="rss" category="Category/@@3000px" xmlUrl="http://localhost/dnnv040505/rss.aspx" />
<outline text="World News" type="rss" category="Category/@@3000px" xmlUrl="http://news.google.com/news?ned=us&topic=w&output=rss" />
<outline text="Sports" type="rss" category="Category/@@3000px" xmlUrl="http://news.google.com/news?ned=us&topic=s&output=rss" />
<outline text="Scout" type="rss" category="Category/@@3000px" xmlUrl="http://rss.scout.com/rss.aspx?&nid=75&cat=8#" /> </outline>
</outline>
</body>
</opml>
http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/48/threadid/168802/scope/posts/threadpage/2/Default.aspx
Copy the OMPL into a text editor and save as either as an opml or xml file. Then load it to your domain and set the Url in Feed Explorer. It's best to use an external file like because if you try to add too much text in the textbox of Feed Explorer it bombs.
Another thing to watch out for is caching. If you save your opml file as xml, then you'll need to add a dummy value to fool the browser into making a new request.
So in the Url box add http://yourdomain.com/youropmlfile.xml?i=1
Whenever you change the xml just increment the i value and your changes will be reflected.