Simple XML - difficult parsing

[GorseFox]

I have been using Simple-XML in PHP 5.2.5 to try and parse an RSS feed
from feedburner. Most of what I want has worked just fine... except
the attempt to extract the content from the tag
"<feedburner:origLink>".

As an example, this tag contains:
<feedburner:origLink>http://someblog.blogspot.com/2008/03/
php.html</feedburner:origLink>

Because this tag uses a special character I used:

$item_origlink = (string) $item->{'feedburner:origLink'};
echo "<p>Original link was: ", $item_origlink , "</p>";

but I never seem to get the content of the tag.

Can anyone offer any suggestions?

Thanks in advance