Использование Proxy при отправке почты через vb.net

Imports System.Net
Imports System.Net.Mail

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim sSender As String = "***@mail.ru"
        Dim sSendTo As String = "****@yandex.ru"
        Dim sSubject As String = "Отчет об ошибке"

        Dim sBody As String = TextBox1.Text
        Dim Msg As New MailMessage(sSender, sSendTo, sSubject, sBody)
        Msg.IsBodyHtml = True
        Dim mc As New SmtpClient("smtp.mail.ru")
        mc.Credentials = New NetworkCredential("***@mail.ru", "пароль")
        mc.EnableSsl = True
        mc.Send(Msg)
    End Sub
End Class