System.ServiceModel.Syndication.SyndicationItem.ElementExtensions.Add with XML prefix

 Hello,
I want to add coordinates to my rss feed like this:
<georss:point>48.67736 -113.638458</georss:point>

This is the code to add:
SyndicationItem.ElementExtensions.Add("georss:point", null, "48.67736 -113.638458");

But the problem is, when a try to save with Rss20FeedFormatter.WriteTo(rssWriter); it's trows an exception:
"Invalid name character in 'georss:point'. The ':' character, hexadecimal value 0x3A, cannot be included in a name."
Could you help me about the problem?
Thanks!

 
 
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