Dim sb As Byte()
      sb = cert.Export(X509ContentType.Pkcs12, "12345")

    Dim newcert As X509Certificate2 = _
     New X509Certificate2(sb, "12345", _
     X509KeyStorageFlags.Exportable Or X509KeyStorageFlags.MachineKeySet Or X509KeyStorageFlags.PersistKeySet)
    Dim store As X509Store = New X509Store(StoreLocation.LocalMachine)
    store.Open(OpenFlags.ReadWrite)
    store.Add(newcert)
    store.Close()

  Function main() As Integer
    main = 0

    If InStr(Command, "/InstallCertToLocal") > 0 Then 'устанавливает e-mail сертификат в LocalMachine и выходит
      Dim str_byte As String = GetSingleOptionFromStr(Command, "InstallCertToLocal")
      If InstallCertToLocalMachine(str_byte) Then
        Return 0
      Else
        Return 1 'код возврата, отличный от нуля означает ошибку
      End If
    End If

...


  Public Function ReInstallCertToLocalMachine(ByRef cert As X509Certificate2) As Boolean
    Try
      Dim sb As Byte()
      sb = cert.Export(X509ContentType.Pkcs12, "12345")


      Dim str_byte = Convert.ToBase64String(sb)
      If IsAdministrator() Then
        ReInstallCertToLocalMachine = InstallCertToLocalMachine(str_byte)
      Else
        Dim cmd_install As String = "/InstallCertToLocal=" & str_byte
        Dim eResult As ExecuteStatus _
         = ExecuteProcess(Application.ExecutablePath, ProcessWindowStyle.Normal, cmd_install, True)
        Select Case eResult
          Case ExecuteStatus.res_OK
            ReInstallCertToLocalMachine = True
          Case Else 'res_FAILED res_CANCEL (здесь не делаем разницы)
            ReInstallCertToLocalMachine = False
        End Select
      End If
    Catch
      Return False
    End Try
  End Function

  Public Function InstallCertToLocalMachine(ByVal the_bytestr As String) As Boolean
    'Выполняется AsAdmin
    Try

      Dim sb As Byte()
      sb = Convert.FromBase64String(the_bytestr)

      Dim newcert As X509Certificate2 = _
       New X509Certificate2(sb, "12345", _
       X509KeyStorageFlags.Exportable Or X509KeyStorageFlags.MachineKeySet Or X509KeyStorageFlags.PersistKeySet)
      Dim store As X509Store = New X509Store(StoreLocation.LocalMachine)
      store.Open(OpenFlags.ReadWrite)
      store.Add(newcert)
      store.Close()
      Return True
    Catch
      Return False
    End Try
  End Function

  Public Function ExecuteProcess(ByVal FilePath As String, _
   Optional ByVal nShow As ProcessWindowStyle = ProcessWindowStyle.Normal, _
   Optional lpParameters As String = vbNullString, _
   Optional LaunchElevated As Boolean = False, _
   Optional useDoEvent As Boolean = False) As ExecuteStatus

    'useDoEvent -использует цикл с DoEvent вместо WaitForSingleObject

    Dim ExecInfo As New ProcessStartInfo
    With ExecInfo
      .FileName = FilePath
      .WindowStyle = nShow
      .WorkingDirectory = IO.Path.GetDirectoryName(FilePath)
      .Arguments = lpParameters
      .UseShellExecute = True
      ' On Microsoft Windows Vista and later, one can use runas instead of Open, in order to execute the
      ' process as an elevated process. In that case, the user will be asked whether he or she wants to
      ' run the process as an administrator.
      If LaunchElevated = True Then
        .Verb = "runas"
      Else
        .Verb = "Open"
      End If
    End With

    Dim procExec As New Process
    Try
      procExec = Process.Start(ExecInfo)
    Catch
      Return ExecuteStatus.res_CANCEL
    End Try

    If useDoEvent Then
      Do While Not procExec.HasExited
        Application.DoEvents()
      Loop
    Else
      procExec.WaitForExit()
    End If
    If procExec.ExitCode = 0 Then
      Return ExecuteStatus.res_OK
    Else
      Return ExecuteStatus.res_FAILED
    End If
  End Function