VB.net Error

I have a .net service version 1.14 Recently I cahnged to version 2.0
 There I'm agetting error as :
<UPC xml:space="preserve"> </UPC> Is there any way to take off xml:space="preserve"
 I want <UPC></UPC>
 On my Code  I'm using a  dataset


Dim mywriter As System.Xml.XmlTextWriter

            mywriter = New System.Xml.XmlTextWriter(file1, System.Text.Encoding.UTF8)

            With mywriter
                .Indentation = 4
                .IndentChar = " "
                .Formatting = .Indentation

                .WriteStartDocument()
                .Formatting = Formatting.Indented
                .WriteStartElement("CMRequest ")
                .WriteAttributeString("xmlns", "http://coursetracks.fheg.follett.com/CMRequest.xsd")
                .WriteStartElement("Header")
                .WriteAttributeString("message-class", "EDIIN")
                .WriteAttributeString("message-id", lawson_id12)
                .WriteAttributeString("message-date", sysdate)
                .WriteEndElement()
                .WriteStartElement("Data")
                .WriteStartElement("LawsonInvoices")
                .WriteAttributeString("xmlns ", "http://coursetracks.fheg.follett.com/LawsonInvoice.xsd")

                LawsonInvoice1.WriteXml(mywriter, XmlWriteMode.IgnoreSchema)

                .WriteFullEndElement()
                .WriteEndDocument()
            End With

            mywriter.Flush()
            mywriter.Close()