[GeoNetwork-devel] Autentication

Hi List,
I’m developing a geonetwork client, I’m trying to login to geonetwork and then make a search. The problem is that I can only have access to the public metadata. I saw that when I login to the Geonetwork web interface, a cookie is created. But when I use the xml.user.login service this does not appear.
What I need to make this searchs with the admin autentication?