theme's custom field and types custom post

hi, i’m trying to use types plugin on my site. That’s a very nice product. but i have a little problem with custom field of my theme. after the creation of new types i can see the custom field of my theme but they doesn’t work. All inserted value disappear after each page update. So i would like to know if the problem is my theme or i have to set something in the plugin types settings?

regards

francesco

http://wordpress.org/plugins/types/