How to Post-Publish a PDF File when CAD Worker is configured for HPGL

I am trying to create a Windchill Publish Rule that will publish a Creo drawing as a PDF file within a WTDocument. The problem is that our default viewables in windchill are HPGL, our CAD worker recipe is to to HPGL and we do not want to change this. So I am finding that even though my publisher rule states output="pdf" I am still getting a .plt file. Here is my rule:-

<?xml version="1.0" encoding="UTF-8"?>

<rules evaluate-rules-on-republish="true" xsi:schemaLocation="http://www.ptc.com PublishRulesSchema.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.ptc.com">

     <authoring-application name="PROE">

      <param-set name="Share with WTDocument">

         <post-publish name="delegate">com.ptc.wvs.server.publish.DefaultPostPublishDelegate</post-publish>

         <post-publish name="name">{AUTHORING_APP}-{EPM_NUMBER}</post-publish>

         <post-publish name="published-content-link">create</post-publish>

                     <post-publish name="folder">Drawings</post-publish>

      </param-set>

        <publish on="checkin" output="pdf" param-set="Share with WTDocument"/>

      <publish on="create-representation" output="pdf" param-set="Share with WTDocument"/>

      <publish on="schedule" output="pdf" param-set="Share with WTDocument"/>

            <publish on="manual-post" output="pdf" param-set="Share with WTDocument"/>

            </authoring-application>

  </rules>

I have been able to get a pdf file using additional-files in the rule, but in this case, my WTDocument has a zip file document containing a .plt file and a .pdf file. Again, this is not my desired result, I just want a pdf file on the WTDocument.

Thanks in advance.