Visual Basic .Net - Consume webservice soap with certificate

Hello:

I have created a windows forms project. I have added the service that I have to consume. I need to create code in order to consume it using certificate. Partial code that I have from a documentation is follwowing (web service reference is called "ClientServeiDeutesProves"):

Try

Dim servei As New ClientServeiDeutesProves.DeutesServiceClient
Dim deutes As ClientServeiDeutesProves.Deutes = New ClientServeiDeutesProves.Deutes()

deutes.Codi = txtIN.Text
deutes.DNINIFContribuent = txtDNI.Text
deutes.Idioma = txtIdioma.Text

System.Net.ServicePointManager.SecurityProtocol = Net.SecurityProtocolType.Tls12

Dim result As ClientServeiDeutesProves.DocumentResult

Try

result = servei.GenerarDocument (deutes)

Catch ex As System.ServiceModel.FaultException(Of ClientServeiDeutesProves.DeutesFault)
MessageBox.Show(ex.Detail.Codi + " - " + ex.Detail.Descripcio)

Return

End Try

'Resposta

If result Is Nothing Then

MessageBox.Show("No s'ha obtingut resposta")

Return

End If

If result.TeDeutes Then

MessageBox.Show("Té deutes")

Else

MessageBox.Show("No té deutes")

End If

If result.Document Is Nothing Then

MessageBox.Show("No s'ha pogut obtenir el document")

Else
MessageBox.Show("Document guardat a c:\temp\docudeutes.pdf")
IO.File.WriteAllBytes("c:\temp\docudeutes.pdf", result.Document)
End If

Catch ex As Exception
MessageBox.Show(ex.Message + vbCrLf + ex.InnerException.Message)
Return
End Try 

Anybody knows how to build it? Thank you very much.

Francesc