How to set nullable property to anonymous

How do i set the properties of "result" to nullable int. The code below doesnt work

<Package><Document><ID>0</ID><UID/><SequenceNumber>0</SequenceNumber></Document><Document><ID/><UID/><SequenceNumber>1</SequenceNumber></Document><Document><ID>2</ID><UID/><SequenceNumber/></Document></Package>

        static void Main(string[] args)
        {
            var result = XDocument.Parse(GetXml()).Root.Elements()
                .Select(x => new
                { 
                    //this doesnt work
                    ID = (int?)(x.Element("ID")),
                    UID = (int?)(x.Element("UID")),
                    SequenceNumber = (int?)(x.Element("SequenceNumber")),
                }).ToList();
        }