You need to pass them as parameters to the bean remote methods. A lot of this depends on how you are designing your servlets and beans. You could make it so that you have setter and getter methods in your bean or you can do it as one method that loads whatever values you want the bean to have.
The first step is creating an RMI connection between the servlet and bean. Once that is established you can run any remote methods on the bean as if the bean was a local object. One thing you have to remember is that any objects you pass between the servlet and bean will need to be serializable.