Hi Thorsten,
You are right, you have several layers of apache to take care as well.
~/etc/apache/proxy-port.conf
ProxyPass http://127.0.0.1:5000/XXX retry=0 disablereuse=On timeout=600
~/etc/apache/apache.conf
Timeout 600
And finally in the system configuration of apache probably in /etc/apache or /etc/httpd depending on your OS, you also need to adjust. Default timeout is 300 sec.
Timeout 600
BR
MF