Character encoding for APT files

When Doxia generates HTML from APT, it appears to force the HTML file  
to use ISO-8859-1, regardless of the original APT's encoding. I don't  
really understand why, since the Maven Doxia Converter supposedly  
generates all files in UTF-8:

   http://maven.apache.org/doxia/doxia-tools/doxia-converter/index.html

I found another user who's having a similar problem:

   http://www.mailinglistarchive.com/users@.../ 
msg21983.html

He demonstrated a technique that appears to tell Doxia which encoding  
to use:

   <plugin>
     <artifactId>maven-site-plugin</artifactId>
       <configuration>
         <outputEncoding>UTF-8</outputEncoding>
       </configuration>
   </plugin>

But this has no effect for me. Is there any way to force Doxia to  
produce UTF-8 HTML for my APT files? Thanks,

Trevor