I made kind of a hacky bounce script to solve the rdf:RDF problem.
It's probably better that the plugin is fixed but this will tide us over until then..
Make a php file with this in it..
Code:
<?
$h = fopen( "http://steampowered.com/rss.xml", "r" );
while (!feof($h))
{
$rss .= fgets($h, 4096);
}
$rss = str_replace( "</channel>", "", $rss );
$rss = str_replace( "</rdf:RDF>", "</channel>\n</rdf:RDF>", $rss );
$rss = str_replace( "content:encoded", "content", $rss );
echo $rss;
?>
Now use the address of that script as your RSS feed (the auto detect thing should be able to figure it out)