datacontractserializer and namespaces

I have a problem trying to deserialize an xml file created from a different namespace. The code I use is

            file = await ApplicationData.Current.LocalFolder.GetFileAsync("EortologioMovingEntries.xml");
        try
        {
            using (IRandomAccessStream stream =
            await file.OpenAsync(FileAccessMode.Read))
            using (Stream inputStream = stream.AsStreamForRead())
            {
                DataContractSerializer serializer = new DataContractSerializer(typeof(Anniversaries), "Anniversaries", "http://ift.tt/1ktVebG");
                tempAnniversaries = serializer.ReadObject(inputStream) as Anniversaries;
            }
        }
        catch (Exception ex)
        {
            error = ex.ToString();
            tempAnniversaries.Entries.Add(new AnniversaryEntry("Ena", DateTime.Now, "skata", PriorityEnum.High));                
        }

Eortologio.Model is the namespace that the file was created. I don't get any exceptions but the tempAnniversaries returns null.

this is the start of the xml file.

<ns2:Anniversaries xmlns:ns2="http://ift.tt/1ktVebG" xmlns:xsi="http://ift.tt/ra1lAU">

Any ideas? Thank you.