President Clinton's national security adviser removed classified documents from the National Archives, hid them under a construction trailer and later tried to find the trash collector to retrieve them, the agency's internal watchdog said Wednesday. The report was issued more than a year after Sandy Berger pleaded guilty and received a criminal sentence for removing the documents. Berger took the documents in the fall of 2003 while working to prepare himself and Clinton administration witnesses for testimony to the Sept. 11 commission. Berger was authorized as the Clinton administration's representative to make sure the commission got the correct classified materials....