focus on a selected row in a ScrollableDataTable

[bin75]

Hi all, I'm using richfaces v3.2.0.
I want to keep the focus on a selected row in a ScrollableDataTable, also after rerendering the table. Below the tab used:

<rich:scrollableDataTable id="idTable" binding="#{classTable.table}" />

in the classTable I have this method to return the selected row:

public Object getRowSelected()
{
Object key = table.getActiveRowKey();
table.setRowKey(key);
Object rowData = table.getRowData();
return rowData;
}

I tried to set the scrollPosition in the table, but it doesn't work very well.
How can I do to keep the focus on the selected row ?

thanks!