XDocument.Validate namespace problems

Question

I have modified the MSDN example to reflect my problem.

When using a namespace I can't get the document to validate as I would expect and when validating a document that doesnt have a namespace it validates regardless of whether or not it has an error in it or not.

Dim errors As Boolean = False

Private Sub XSDErrors(ByVal o As Object, ByVal e As ValidationEventArgs)
    Console.WriteLine("{0}", e.Message)
    errors = True
End Sub

Private Function AddNameSpace(ByVal xDoc As XDocument, ByVal ns As XNamespace) As XDocument
    For Each element As XElement In xDoc.Descendants
        element.Name = ns + element.Name.LocalName
    Next
    Return xDoc
End Function

Sub Main()
    Dim xsdMarkup As XElement = _
        <xsd:schema xmlns:xsd='http://www.w3.org/2001/XMLSchema' xmlns="http://somenamespace.com" targetNamespace="http://somenamespace.com">
            <xsd:element name='Root'>
                <xsd:complexType>
                    <xsd:sequence>
                        <xsd:element name='Child1' minOccurs='1' maxOccurs='1'/>
                        <xsd:element name='Child2' minOccurs='1' maxOccurs='1'/>
                    </xsd:sequence>
                </xsd:complexType>
            </xsd:element>
        </xsd:schema>
    Dim schemas As XmlSchemaSet = New XmlSchemaSet()
    schemas.Add("http://somenamespace.com", xsdMarkup.CreateReader)

    Dim doc1 As XDocument = _
        <?xml version='1.0'?>
        <Root>
            <Child1>content1</Child1>
            <Child2>content1</Child2>
        </Root>

    Dim doc2 As XDocument = _
        <?xml version='1.0'?>
        <Root>
            <Child1>content1</Child1>
            <Child3>content1</Child3>
        </Root>

    Dim ns As XNamespace = "http://somenamespace.com"
    doc1 = AddNameSpace(doc1, ns)

    Console.WriteLine("Validating doc1")
    errors = False
    doc1.Validate(schemas, AddressOf XSDErrors)
    Console.WriteLine("doc1 {0}", IIf(errors = True, "did not validate", "validated"))

    Console.WriteLine()
    Console.WriteLine("Validating doc2")
    errors = False
    doc2.Validate(schemas, AddressOf XSDErrors)
    Console.WriteLine("doc2 {0}", IIf(errors = True, "did not validate", "validated"))

End Sub

Output:

Validating doc1

The element 'Root' in namespace 'http://somenamespace.com' has invalid child element 'Child1' in namespace 'http://somenamespace.com'. List of possible elements expected: 'Child1'.

doc1 did not validate

Validating doc2

doc2 validated