Running loolwsd under port 80 (apache proxy conf and loolwsd.xml)

I try to set up the nextcloud server behind an apache proxy server. The apache proxy uses https for the internet side and http for the intranet side. So that only the apache proxy server is seen from the internet. The apache proxy server redirects the client requests to a intranet nextcloud server using http. This works already .
Now I try to configure the apache proxy to redirect requests for collabora online. Because nextcloud uses http I have to use http for collabora online (loolwsd).
How do I have to rewrite the apache proxy conf file for loolwsd using http on the intranet nextcloud server? And how do I have to modify the loolwsd.xml file.

Kind regards