Using Ant Plugins with the Ant Plugin

I have an ant build script that uses the jsmin plugin ant task.  It works fine from the command line, so I know the script is fine.  I added the jsmin.jar file to the JetBrains/IntelliJ 11.1/lib/ant/lib directory.  In the build script I have:

  <taskdef name="jsmin" classname="net.matthaynes.jsmin.JSMin_Task"/>

  <target name="minify" if="do.minify" depends="init">
    <echo>Minifying JavaScript Files...</echo>
    <jsmin destdir="${dst.dir}/content" dontMinify=".min.js">
      <fileset refid="javascript"/>
    </jsmin>
  </target>

Idea marks the jsmin task as an error and the hover states "Cannot resolve symbol 'jsmin'".  Pressing Alt-Enter on it doesn't bring up any options.

How can I get Idea to recognize the taskdef?
  (*Chris*)