New York--Cantor Fitzgerald, the bond brokerage firm that lost 658 employees in the Sept. 11 attacks on the World Trade Center, is telling its wrenching story in a national advertising campaign that launched Wednesday. A full-page ad in The New York Times on Wednesday reads, "Tragedy forced Matt Claus to learn quickly." It describes how Claus, an information technology manager, got eSpeed, the firmâs global electronic marketplace and trading technology business, back up and running within two days of the attack. The ad is one of three print ads and nine TV spots released this week. Cantor and eSpeed had planned to launch their first major ad campaign on Sept. 17. That campaign was canceled.