If you look at the article, the statement from Obamma’s spokesperson is in quotes. The part about Charlie Payne is from the reporter. It could be just another lazy reporter who did not do his research.
“Aides said Tuesday that his grandmother’s brother, Charlie Payne, helped liberate a Buchenwald sub-camp in April 1945 as part of the 89th Infantry Division.”
http://www.cbsnews.com/stories/2008/05/27/politics/main4130449.shtml