Connect pritunel to a proxy server

Hi .
I have a issue how to connect a pritunl server to a proxy server. I have an http proxy server and a pritunl server. I would like to connect them in such a way that the pritunl server receives all internet data from the http proxy server and when the vpn users coneect to the pritunl , they receive the internet from the proxy server.

The Pritunl server won’t route traffic to an HTTP proxy.

How do I create this structure?