How to update jpa element from list when it is unmanaged?

Environment:

• JBoss 5
• Java EE 5
• Java 7

I have an entity course that have a list of students with a bidirectional relation.

VIEW

I have a view for course that shows a list of students but I also have a view for student edition. Every time it shows the view the elements are unmanaged.

When I modify a student using jpa

<T> T merge(T entity)

I have a new entity and then I would have to update the array list of course or replace the element with the new one.

Is there a way to do this more easily?