can some1 please convert this htaccess to nginx rewrite?

[mike]

for vbseo this is all i have for one of my clients:

        location /forum/ {
                rewrite
^/forum/((urllist|sitemap_).*\.(xml|txt)(\.gz)?)$
/forum/vbseo_sitemap/vbseo_getsitemap.php?sitemap=$1 last;
                if ($request_filename ~ "\.php$") {
                        rewrite ^(.*)$ /forum/vbseo.php?vbseourl=$1 last;
                }
                if (!-e $request_filename) {
                        rewrite ^/forum/(.*)$ /forum/vbseo.php?vbseourl=$1 last;
                }
        }

site also has other things (blogs etc) that have their own location
blocks and it seems to all work great.