Setting up RStudio Server as subdirectory

I installed RStudio Server and I can connect to it at localhost:8787. I want to access it from localhost/rstudio (really myserver.com/rstudio). I'm following the instructions here. However, I'm getting "URL /rstudio not found on server."

Not sure if this is the problem, but the system is running lighttppd, not httpd, and there is no file corresponding to /etc/httpd/conf.modules.d/00-proxy.conf. Only, /etc/lighttpd/conf-available/90-javascript-alias.conf, and /etc/lighttpd/conf-enabled/90-javascript-alias.conf links to it.

/etc/apache2/sites-enabled/rstudioserver.conf:

<VirtualHost *:80>

        #ServerAdmin webmaster@localhost
        #DocumentRoot /var/www/html

        ErrorLog ${APACHE_LOG_DIR}/error.log
        CustomLog ${APACHE_LOG_DIR}/access.log combined


        <Proxy *>
                Allow from localhost
        </Proxy>

        ProxyPassMatch ^/rstudio/s/([a-z0-9]+)/(websocket|.*/websocket)/$ ws://localhost:8787/p/$1/$2/
        ProxyPass /rstudio/ http://localhost:8787/
        ProxyPassReverse /rstudio/ http://localhost:8787/
        ProxyRequests Off
</VirtualHost>

Recent Questions...