mbstring: php.ini: need help understanding some settings/functions

I am trying to use the mbstring library so I can receive user input in japanese and then put it into my pgsql DB. But the documentation is really sparse and sometimes confusing. I can't understand some of the functions provided by mbstring or it's settings in php.ini. Some functions/settings don't seem to do what they say or the explanation of how to use them is missing. For example I tought internal_encoding was used along with --enable-mbstring-enc-trans so that any input would be automatically converted to the internal encoding. But it is isn't. When I check what charset POST data is in it is always in the charset the user used, never in the internal_encoding charset. I have to manually convert myself using mbstring functions. I guess I don't understand what the settings of mbstring in php.ini and at compile time really do. Can someone explain to me what is the use of: --enable-mbstring-enc-trans at compile time mb_http_input() mb_http_output() mb_internal_encoding() mb_language() mb_output_handler() Thanks! Jc