Opennebula XML-RPC API in PHP

I try to connect to opennebula using xmlrpc ip:2633/RPC2 and receive a faultcode
i think xmlrpc is not documented well in wiki so any one can give me a sample code that connect to opennebula and get a vm info with id 12 for example ?
thank you very much

You may want to look to:

(RUBY Examples)
3.- (RUBY API)
4.- Take a look to the CLI of OpenNebula

In your case you probably need to pass the session (user:pass) string.