This question has been answered by rodoneill. See the first response.
Articles has a setting to control the alias format, though I'm not sure where it is or if it will solve your problem.
There is no easy solution to this. It's done in the core/components/articles/model/articles/article.class.php file, around line 286
$uri = rtrim($containerUri,'/') .'/'. rtrim($furlTemplate);
$uri = rtrim($furlTemplate);