Vitali Klitschko's advisor Shelly Finkel and Hasim Rahman's promoter Don King are in the process of negotiating the WBC heavyweight champion's mandatory defense against the last man to knock Lennox Lewis stiff. Earlier in the week, Boxingtalk.com was informed that April 23 was the working date, however moments ago Finkel informed Boxingtalk.com that Klitschko-Rahman would probably take place in late April or May. "But probably May," said Finkel, who described his ongoing negotiations with Don King as "very cordial."  A couple of weeks ago, Klitschko mentioned the possibility of an interim fight, but now that's out of the equation as Klitschko-Rahman will be next. Don King was unavailable for immediate comment. BT will continue to keep you updated, until then REMEMBER WHERE YOU HEARD IT FIRST! (3:30 PM ET)