This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
the ice:selectOneMenu is populated by an ArrayList of list items. You can see an example of in the Component Showcase on the ICEsoft website.
To populate that list you don't need any special JSF functionality. Just parse the XML file using whatever XML parser you like to add the data elements to the ArrayList. That list is assigned to the ice:selectOneMenu control in your view.