10.11 updates from a 10.10 update server

Has anyone has any luck getting a 10.10 (Yosemite) server running software updates, to download and serve 11.11.1 or 11.11.2 etc software updates for El Capitan clients.

So far I stopped the software update service, added:

RewriteCond %{HTTP_USER_AGENT} Darwin/14

RewriteRule ^/index\.sucatalog$ http://%{HTTP_HOST}/cgi-bin/Softwar...n-lion-snowleopard-leopard.merged-1.sucata log

to the <IfModule mod_rewrite.c> section of /Library/Server/Software Update/Config/swupd.conf

also added:

<string>index-11.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.su catalog</string>

to the OtherCatalogs area of /Library/Server/Software Update/Config/swupd.plist

and restarted the swupdate service. I have also rebooted the server but still not seeing any 10.11 updates.

Has anyone tackled this already?

Thanks,

Christian