How to add a extension such as XEP-0133

Hi I’m trying to find out if its possibble to add the xep-0133 extension to xiff. I’m using Openfire server. I added this extention in the server administration under the external extentions. With this subdomain: http://jabber.org/protocol/admin#announce but when i make a request like:

<iq from="admin@myserver.hu/xiff" id=“info-1” to=“myserver.hu” type=“get”>

<query xmlns=“http://jabber.org/protocol/disco#info” />

</iq>

it still doesnt show up as a feature .

I’m guessing that i will have to add the extension from xiff, but i’m not sure how its done. I would be very thankfull if somebody could paste some simple example, about adding an extention, because i couldnt find any on this forum or the internet and the also documentation doesn’t contain any.

thanks