Openfire VoIP

Hello community!
It’s almost a month as I setted up my Openfire server.

I’ve seen tons of posts regarding voice calls using openfire with plugins an so on, but i didn’t find anything helpful for me(

I want to be able to make voice calls between 2 users, using Spark or whatever is possibile to use for this.
Can you please give me any real examples, clear guides or any ideas?
You help will be appreciated.
Thank you.

See http://community.igniterealtime.org/blogs/ignite/2012/06/08/a-new-jingle-voice-c hat-plugin-for-spark