how to save (insert,del,update) dirty objects with <Set> agg

[hanasakijiji]

If the ejb is called with

ejb.getStuff().add(someInstance);
* how to make jboss add the new row?

or

ejb.getStuff().get(4).setValue("my new value");
* how to make jboss update the row?

or

Set<List> set = new HashSet<String>();
ejb.setStuff(set);
* how to make jboss delete and insert the old/new rows?