I\'m using .NET\'s SyndicationFeed to create RSS and ATOM feeds. Unfortunately, I need HTML content in the description element (the Content property of the SyndicationItem)
It might be too late but I leave my solution. I added it as a ElementExtension then it works for me. My environment is .NET 4.5.
XNamespace nsDefault = "http://www.w3.org/2005/Atom";
var content = new XElement(nsDefault + "content");
content.Add(new XCData("Item Content"));
item.ElementExtensions.Add(new SyndicationElementExtension(content));