Adapting the RewriteRule to nginx under engine SocialEngine

Friends, help. Try to run SocialEngine directly under nginx/php-fpm without Apache. In three simple RewriteRule, but sit for a second hour without success blunt.

Here's the original:

RewriteCond %{REQUEST_URI} /index\\.php
RewriteRule (.*) index.php?rewrite=2 [L,QSA]

RewriteCond %{REQUEST_URI} /$
RewriteRule (.*) index.php?rewrite=1 [L,QSA]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?rewrite=1 [L,QSA]

As it will be in the nginx configuration?
Most of the questions is not previously familiar to me flag QSA. I feel a catch somewhere in it.