Editable JSF datatable - Adding new (empty) rows.

JSF 1.2 with JBoss 4.2. ajax4jsf

I have a complex JSF form with many components. One of the component is a data table. Initially, the data table is empty (no rows), just the header. I need to provide an Add button, when a user clicks this a new (empty) row appears. The row has various input text components. The user can fill in the data and click add (as many times as they like). The backing bean is in 'request' scope.

I have tried many ways to solve this problem but none seem to work.

1. use java script to generate the empty row. The id's I generated should match the JSF data table component. (form:datatable-id:rowindex:txtInputId). However, doing this does not seem to work. The backing bean is not being updated. Also, if there is any other validation error on the form, the entered line data is disappearing.

2. use the following tag to make a call to a listener on the backing bean
      <a4j:commandButton value="Add"
                                 immediate="true"
                                 actionListener="#{claimform.addNewClaimLine}"
                                 reRender="lines"/>
Where lines is the entire data table id.
But in the listener, there is no way for me to get the data in the table. I was hoping to add the data to the backing bean and also add a new empty item and have the lines re-rendered. There are obviously issues with the scope of the bean as well.

Does anyone know of any simple way of doing this. I don't want to submit the entire form because it may not be complete as there are additional fields on the form. Any help will be greatly appreciated.