Encoding issue: StringStream over XmlDocument.OuterXml feeds invalid XML to XslCompiledTransfrom

[icraftsoftware]

The following test code illustrates the issue

[Fact]
public void ValidateTransform()
{
  var templateTargetEnvelope = EnvelopeFactory.Create<Envelope>();
  var templateTargetEnvelopeStream = new StringStream(templateTargetEnvelope.OuterXml);

  var batchContentWithParts = MessageBodyFactory.Create<Batch.Content>(MessageBody.Samples.LoadString("Message.BatchContent.xml"));
  var batchContentWithPartsStream = new StringStream(batchContentWithParts.OuterXml);
  
  Given(
      input => input
        .Message(templateTargetEnvelopeStream)
        .Message(batchContentWithPartsStream))
    .Transform
    .OutputsXml(
      output => output
        .ConformingTo<Envelope>()
        .ConformingTo<Batch.Release>()
        .WithStrictConformanceLevel())
    .Validate();
}

and produces the following exception System.Xml.XmlException Name cannot begin with the '.' character, hexadecimal value 0x00. Line 1, position 40..