[tex4ht] controlling output suffix with xhmlatex

[William F Hammond]

Greetings,

I've not written here before.

Question.  When I use xhmlatex to generate xhtml+mathml from, say,
foo.tex the final output is given the filename foo.html.

Is there a way to force it to be given the filename foo.xhtml?
I would expect the suffix to be a command line option for "t4ht".
At the moment I'm not even seeing why mzlatex outputs foo.xml
rather than foo.html.

Thanks.

                                    -- Bill