Basically q2a offers 5 types of URLs, see options in admin/general:
/123/why-do-birds-sing (requires htaccess file)
/index.php/123/why-do-birds-sing
/?qa=123/why-do-birds-sing
/?qa=123&qa_1=why-do-birds-sing
/index.php?qa=123&qa_1=why-do-birds-sing
To achieve what you like, you need to select the first one.
Then you override functions that generate the URLs, for instance for the question list:
function qa_q_path_html($questionid, $title, $absolute=false, $showtype=null, $showid=null)
/*
Return the HTML representation of the URL for $questionid - other parameters as for qa_q_path()
*/
{
$title = ''; // added to have no additional information in the URL
return qa_html(qa_q_path($questionid, $title, $absolute, $showtype, $showid));
}
Hope that helps,
Kai