Has anyone used XHTML Doclet, and can you provide some hints as to how to get it to work successfully?

I run it like this:

\sunjdk\bin\javadoc -doclet net.sourceforge.xhtmldoclet.Doclet  
         -docletpath c:\sw\java\XHTML_Doclet_0.4.jar -d <output>
         [class files here]

(all on one line)

When I run it I get this:

javadoc: error - In doclet class net.sourceforge.xhtmldoclet.Doclet,  method validOptions has thrown an exception java.lang.reflect.InvocationTargetException
java.lang.Error: Fatal: Resource (net.sourceforge.xhtmldoclet.resources.doclet) for javadoc doclets is missing.
        at com.sun.tools.doclets.internal.toolkit.util.MessageRetriever.getText(MessageRetriever.java:110)
        at com.sun.tools.doclets.internal.toolkit.util.MessageRetriever.getText(MessageRetriever.java:92)
        at com.sun.tools.doclets.internal.toolkit.util.MessageRetriever.getText(MessageRetriever.java:81)
        at com.sun.tools.doclets.internal.toolkit.Configuration.getText(Configuration.java:634)
        at com.sun.tools.doclets.internal.toolkit.Configuration.generalValidOptions(Configuration.java:515)
        at net.sourceforge.xhtmldoclet.Config.validOptions(Unknown Source)
        at net.sourceforge.xhtmldoclet.Doclet.validOptions(Unknown Source)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.tools.javadoc.DocletInvoker.invoke(DocletInvoker.java:269)
        at com.sun.tools.javadoc.DocletInvoker.validOptions(DocletInvoker.java:198)
        at com.sun.tools.javadoc.Start.parseAndExecute(Start.java:317)
        at com.sun.tools.javadoc.Start.begin(Start.java:128)
        at com.sun.tools.javadoc.Main.execute(Main.java:41)
        at com.sun.tools.javadoc.Main.main(Main.java:31)
1 error

It seems like it ought to just work. What am I doing wrong?