Here was what was in the acs-lang doc (for shift_jis)
ns_section ns/parameters
ns_param HackContentType 1
ns_param URLCharset shift_jis
ns_param OutputCharset shift_jis
ns_param HttpOpenCharset shift_jis
You might try setting the couple you are missing.
Is also has things like this:
ns_section ns/mimetypes
...
ns_param .tcl "text/html; charset=shift_jis"
ns_param .adp "text/html; charset=shift_jis"
but I am not sure what that does in the context of the
request processor.