what i had to do was to install mod proxy

sudo aptitude install libapache2-mod-proxy-html

add to /etc/apache2/httpd.conf

ProxyRequests off 
ProxyPass /myapp http://127.0.0.1:8000/myapp 
ProxyHTMLURLMap http://127.0.0.1:8000/myapp /myapp

and execute the following commands

sudo ln -s /etc/apache2/mods-available/proxy_http.load /etc/apache2/mods-enabled/proxy_http.load 
sudo a2enmod proxy

now change in /etc/apache2/mods-enabled/proxy.conf

Deny from all

to

Allow from all

finally

sudo /etc/init.d/apache2 restart

yes i did not excatly know what I did in every step and there may be room for improvements but it works :)