The CallTarget uses a technique to route the calls to handleOutput and handleErrorOutput to the appropriate task by utilizing protected versions of the handle... methods. There's a bug in the ant-contrib project (link below) that shows the need for public access to those methods. ant-contrib bug: http://sourceforge.net/tracker/index.php?func=detail&aid=677097&group_id=36177&atid=416920
fixed in cvs. since they were protected you always had a workaround called subclassing...
will be available in Ant 1.5.2.