> but i cannot use the last node for setting the selection, unless i got the > new path for the node, which is somehow very tricky :-(
Not sure what you mean. When you add an item to a list, the add() method returns the index of the new item. So if you add a node to the branch at path [0][1][2] and add() returns 3, the path to the new node would be [0][1][2][3].
