Hi I'm new to jsf/icefaces. I have a problem how to solve this complex situation:

a user can use a button, then he will get a new selection screen. Om that screen he can select a value (that value needs to be passed to the former screen) this selection function will be used by a lot of other programs, how to solve? who can help??

You need to store that value in a bean the important part is the scope of the bean. If it has to be used by any page in an application, then you can use session scope. JSF 2 comes with new scope called view but its good for a view only.