Enabling Console output for exec ANT task

Question

Inside eclipse I'm launching an html page with a swf embedded from ANT using the following Macrodef:

<macrodef name="runhtml">
   <attribute name="url" />
   <attribute name="browser" default="${app.browser.firefox}" />
   <sequential>
      <exec
         executable="open"
         vmlauncher="true"
         spawn="false"
         failonerror="true">
         <arg line="-a '@{browser}'" />
         <arg line="@{url}" />
      </exec>
   </sequential>
</macrodef>

Despite the fact that the swf contains traces, I am not getting any output from them in the console. What could be causing this?