Setup reverse proxy on OpenLiteSpeed (no console)

Hi at all,
I'm trying to add reverse proxy to my virtual host, but I'm facing some issues with the configuration.
I read several guides about that, but they are all for the console version (the one that runs at port 7080). I can't follow these tutorials because on directadmin the console is read-only, so I have to on the manual way.

On my old server running directadmin on apache I just insert this and it works.
ProxyPreserveHost On
ProxyPass /
ProxyPassReverse /
RewriteEngine on
RewriteCond %{HTTP:UPGRADE} ^WebSocket$ [NC]
RewriteCond %{HTTP:CONNECTION} Upgrade$ [NC]
RewriteRule /(.*) ws://$1 [P]

When I try to add it on my openlitespeed server in "custom httpd config" I have this errors :
[PlainConf] [] Not support [proxypass /] in file /usr/local/directadmin/data/users/admin/openlitespeed.conf:13
[PlainConf] [] Not support [proxypassreverse /] in file /usr/local/directadmin/data/users/admin/openlitespeed.conf:14
[PlainConf] [] Not support [rewriteengine on] in file /usr/local/directadmin/data/users/admin/openlitespeed.conf:15
[PlainConf] [] Not support [rewritecond %{HTTP:UPGRADE} ^WebSocket$ [NC]] in file /usr/local/directadmin/data/users/admin/openlitespeed.conf:16
[PlainConf] [] Not support [rewritecond %{HTTP:CONNECTION} Upgrade$ [NC]] in file /usr/local/directadmin/data/users/admin/openlitespeed.conf:17
[PlainConf] [] Not support [rewriterule /(.*) ws://$1 [P]] in file /usr/local/directadmin/data/users/admin/openlitespeed.conf:18

Like all my config is not supported on openlitespeed.

Can you give me an hint on how to setup the reverse proxy server on openlitespeed?