Using "FOR XML" with XML Serialization with DATETIME type

I'm having issues trying to add some dates to a pre-existing class that is loaded via XML Serialisation, and it's not doing what I thought it should do.

I knocked up a basic test with SQL of (where EffectiveFrom and EffectiveTo are declared as DATETIME)

SELECT  o.EffectiveFrom AS [@EffectiveFrom],
        开发者_JS百科o.EffectiveTo   AS [@EffectiveTo],
FROM    dbo.MyObject o
FOR XML PATH('MyObject'), ROOT('ArrayOfMyObject'), type

Which gives XML:

<ArrayOfMyObject>
  <MyObject EffectiveFrom="1977-11-23T00:00:00" EffectiveTo="2050-01-01T00:00:00" />
</ArrayOfMyObject>

Then I've declared the class as:

public class MyObject
{
    [XmlAttribute("EffectiveFrom")]
    public DateTime EffectiveFrom { get; set; }

    [XmlAttribute("EffectiveTo")]
    public DateTime EffectiveTo { get; set; }
}

However, the properties aren't being set. I might just be having "a thick day" and missing the blinding obvious, but I would've expected this to "just work" -- any ideas why it isn't?

Will I realy have to create some string properties that call Date.ParseExact() on the set, and ToString() on the get, flagging that for XML Serialisation, and flagging the real properties as XmlIgnore()?

I don't see a closing tag for < MyObject > ?

Appears to "just work" with SQL Server 2008, where as we'd been using SQL Server 2005 beforehand