apache 2.2 - Empty rewrite.log on Windows, RewriteLogLevel is in httpd.conf

I am using mod_rewrite on Apache 2.2, Windows 7, and it is working ... except I don't see any logging information.

I added these lines to the end of my httpd.conf:

RewriteLog "c:\wamp\logs\rewrite.log"
RewriteLogLevel 9

The log file is created when Apache starts (so it's not a permission problem), but it remains empty. I thought there might be a conflicting RewriteLogLevel statement somewhere, but I checked and there isn't.

What else could cause this?

Could this be caused by Apache not flushing the log file? (I closed it by hitting CTRL-C on the httpd.exe command ... this caused the access logs to be flushed to disk, but still nothing in rewrite.log)

My (partial) httpd-vhosts.conf:

    ServerAdmin webmaster@localhost
    ServerName my.domain.com
    DocumentRoot c:\wamp\www\folder

    
        Options -Indexes FollowSymLinks MultiViews
        AllowOverride None

        Order allow,deny
        allow from all

        
            RewriteEngine On
            RewriteBase /

            RewriteRule . everything-redirects-to-this.php [L]