HTTPS, proxy e webhooks no apache

Question

Estou trabalhando com um cliente que configurou um servidor apache para usar https e um proxy, mas não estamos recebendo informações de webhooks. O que precisamos adicionar à configuração para permitir o retorno de chamadas http?

<IfModule mod_ssl.c>
    RequestHeader set X-Forwarded-Proto 'https'
    <VirtualHost _default_:443>
     ServerAdmin webmaster@localhost
     DocumentRoot /home/xxx/ui/current
     <Directory /home/xxx/ui/current>
          Options FollowSymlinks
          AllowOverride none
          Require all granted
     </Directory>

     <Directory "/home/xxx/src/static">
          Options FollowSymLinks
          AllowOverride None
          Require all granted
   </Directory>

  ## Proxy rules
         ProxyRequests Off
         ProxyPass /ws ws://127.0.0.1:8001
         ProxyPassReverse ws://127.0.0.1:8001
## Rewrite rules
         RewriteEngine On
         RewriteRule ^/api/(static|sd)/?$ /api/static/docs/ [R,L]
         RewriteRule ^/api/static(.*) /home/xxx/src/static$1 [L]
         RewriteRule ^/api(|/|/doc|/docs)$ /api/docs/ [R,L]
         RewriteRule ^/api(/(.*))? http://localhost:8000/api$1 [P,L]
         RewriteCond %{REQUEST_URI} !^/ws/
         RewriteCond %{LA-U:REQUEST_FILENAME} !-f
         RewriteCond %{LA-U:REQUEST_FILENAME} !-d
         RewriteRule ^ /index.html [L,NS]
         ErrorLog ${APACHE_LOG_DIR}/error.log
         CustomLog ${APACHE_LOG_DIR}/access.log combined
            #   SSL Engine Switch:
            #   Enable/Disable SSL for this virtual host.
            SSLEngine on
            SSLCertificateFile /etc/apache2/ssl/server.crt