Sub SignXML(doc As XmlDocument, cert As X509Certificate2)
        Dim signedXml As New SignedXmlWithId(doc)

        signedXml.SigningKey = cert.PrivateKey
        signedXml.SignedInfo.CanonicalizationMethod = Security.Cryptography.Xml.SignedXml.XmlDsigExcC14NTransformUrl

        Dim refBody As New Reference()
        refBody.Uri = "#id-5"

        Dim refTmSt As New Reference()
        refTmSt.Uri = "#Timestamp-4"

        Dim trnBody As New XmlDsigExcC14NTransform()
        Dim trnTsSt As New XmlDsigExcC14NTransform()

        refBody.AddTransform(trnBody)
        refTmSt.AddTransform(trnTsSt)

        signedXml.AddReference(refTmSt)
        signedXml.AddReference(refBody)

        signedXml.ComputeSignature()
        Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()

        doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))

        Dim SignedXMLString = doc.OuterXml
    End Sub

'этот класс для обхода проблемы нечитаемости префикса ID 
Public Class SignedXmlWithId
    Inherits SignedXml
    Public Sub New(xml As XmlDocument)
        MyBase.New(xml)
    End Sub

    Public Sub New(xmlElement As XmlElement)
        MyBase.New(xmlElement)
    End Sub

    Public Overrides Function GetIdElement(doc As XmlDocument, id As String) As XmlElement
        ' check to see if it's a standard ID reference
        Dim idElem As XmlElement = MyBase.GetIdElement(doc, id)

        If idElem Is Nothing Then
            Dim nsManager As New XmlNamespaceManager(doc.NameTable)
            nsManager.AddNamespace("wsu", "http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd")

            idElem = TryCast(doc.SelectSingleNode((Convert.ToString("//*[@wsu:Id=""") & id) + """]", nsManager), XmlElement)
        End If

        Return idElem
    End Function
End Class