htaccess – Server Subdirectory With Different Name Than URL Subdirectory

So I have a client with an odd setup that I can’t quite figure out and I thought someone here might know the answer. I’m not sure they want the site shared, so I’ll use “mydomain.com” for the sake of explanation.

Their wordpress URL is setup like http://mydomain.com/blog .

However, on the server (Apache), the actual folder is called “wordpress” NOT ”blog”.

The .htaccess is located in the “wordpress” folder (full server path is /var/www/wordpress/) and looks like this:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /blog/
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

There is no .htaccess in /var/www/

In General Settings they have this:

WordPress Address: http://mydomain.com/blog

Site Address: http://mydomain.com/blog

This works fine on WordPress pages, posts and categories. But some plugins (gravity forms, nextgen) will strip out the “blog” portion of the URL when using them. So for example a Gravity Form will try to submit to http://mydomain.com instead of http://mydomain.com/blog which will cause an error.

My guess is that .htaccess is configured wrong but .htaccess and regular expressions are my weak point and I’m hoping someone can help.