FOPNGSerializer and upgrade from cocoon 2.2.0 to cocoon 3.0

I used FOPNGSerializer (I forgot why) and the configuration (I use the 
font englischeschjoit.ttf ):
  <map:components>
   <map:serializers default="html">
      <map:serializer name="fo2pdf" logger="sitemap.serializer.fo2pdf" 
src="org.apache.cocoon.blocks.fop.FOPNGSerializer" 
mime-type="application/pdf">
       <user-config>fop-config.xml</user-config>
     </map:serializer>
      </map:serializers>
     </map:components>
But this seems not to work.
How is such a configuration possible under cocoon 3.0.