how to call an Ant task

Hi
I have a build.xml that has the following:

<target name="generate-Metro-jaxws">
      <taskdef name="wsimport" classname="com.sun.tools.ws.ant.WsImport">
         <classpath refid="metro.classpath"/>
      </taskdef>
      <wsimport destdir="build/classes"
         sourcedestdir="src" wsdl="etc/${wsdl.file}"/>
   </target>

I need to call the "generate-Metro-jaxws task (or should I say, target) to generate some Java classes.

I would be grateful for any suggestions.

thanks
Ilango