http://bugs.winehq.org/show_bug.cgi?id=26586
--- Comment #7 from ocean04@suomi24.fi 2011-07-28 09:12:17 CDT --- About that second solution.
Simply if there is user & password given ->
xmlhttp.setrequestheader('Authorization', 'Basic '+base64encode(edit2.text+':'+edit3.text));
Should be easy, if there is already base64 function in wine?